Bump gatsby-plugin-sharp from 2.6.12 to 2.6.18

Bumps [gatsby-plugin-sharp](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-plugin-sharp) from 2.6.12 to 2.6.18.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-sharp/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-plugin-sharp@2.6.18/packages/gatsby-plugin-sharp)

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -15,7 +15,7 @@
     "gatsby-plugin-remove-serviceworker": "^1.0.0",
     "gatsby-plugin-robots-txt": "^1.5.1",
     "gatsby-plugin-sass": "^2.3.10",
-    "gatsby-plugin-sharp": "^2.6.12",
+    "gatsby-plugin-sharp": "^2.6.18",
     "gatsby-source-filesystem": "^2.3.12",
     "gatsby-transformer-sharp": "^2.5.10",
     "http-status-codes": "^1.4.0",

yarn.lock

@@ -4492,15 +4492,6 @@ currently-unhandled@^0.4.1:
   dependencies:
     array-find-index "^1.0.1"
 
-cwebp-bin@^5.0.0:
-  version "5.1.0"
-  resolved "https://registry.yarnpkg.com/cwebp-bin/-/cwebp-bin-5.1.0.tgz#d5bea87c127358558e7bf7a90a6d440d42dcb074"
-  integrity sha512-BsPKStaNr98zfxwejWWLIGELbPERULJoD2v5ijvpeutSAGsegX7gmABgnkRK7MUucCPROXXfaPqkLAwI509JzA==
-  dependencies:
-    bin-build "^3.0.0"
-    bin-wrapper "^4.0.1"
-    logalot "^2.1.0"
-
 cyclist@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/cyclist/-/cyclist-1.0.1.tgz#596e9698fd0c80e12038c2b82d6eb1b35b6224d9"
@@ -5694,17 +5685,6 @@ evp_bytestokey@^1.0.0, evp_bytestokey@^1.0.3:
     md5.js "^1.3.4"
     safe-buffer "^5.1.1"
 
-exec-buffer@^3.0.0:
-  version "3.2.0"
-  resolved "https://registry.yarnpkg.com/exec-buffer/-/exec-buffer-3.2.0.tgz#b1686dbd904c7cf982e652c1f5a79b1e5573082b"
-  integrity sha512-wsiD+2Tp6BWHoVv3B+5Dcx6E7u5zky+hUwOHjuH2hKSLR3dvRmX8fk8UD8uqQixHs4Wk6eDmiegVrMPjKj7wpA==
-  dependencies:
-    execa "^0.7.0"
-    p-finally "^1.0.0"
-    pify "^3.0.0"
-    rimraf "^2.5.4"
-    tempfile "^2.0.0"
-
 execa@1.0.0, execa@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/execa/-/execa-1.0.0.tgz#c6236a5bb4df6d6f15e88e7f017798216749ddd8"
@@ -6141,7 +6121,7 @@ file-type@^3.8.0:
   resolved "https://registry.yarnpkg.com/file-type/-/file-type-3.9.0.tgz#257a078384d1db8087bc449d107d52a52672b9e9"
   integrity sha1-JXoHg4TR24CHvESdEH1SpSZyuek=
 
-file-type@^4.2.0, file-type@^4.3.0:
+file-type@^4.2.0:
   version "4.4.0"
   resolved "https://registry.yarnpkg.com/file-type/-/file-type-4.4.0.tgz#1b600e5fca1fbdc6e80c0a70c71c8dba5f7906c5"
   integrity sha1-G2AOX8ofvcboDApwxxyNul95BsU=
@@ -6503,10 +6483,10 @@ gatsby-cli@^2.12.48:
     yargs "^15.3.1"
     yurnalist "^1.1.2"
 
-gatsby-core-utils@^1.3.6:
-  version "1.3.6"
-  resolved "https://registry.yarnpkg.com/gatsby-core-utils/-/gatsby-core-utils-1.3.6.tgz#5a001593276b0c1cc4a3c6c9a34da428e9374590"
-  integrity sha512-ptd//w6MX1/hUGO2KBffSUKSYIVU3SFRM2cKXN3CMmCQvn8ul2OHCjpNY8MyZQuluWk8nRtvhjEGrl+KJtcOnw==
+gatsby-core-utils@^1.3.11, gatsby-core-utils@^1.3.6:
+  version "1.3.11"
+  resolved "https://registry.yarnpkg.com/gatsby-core-utils/-/gatsby-core-utils-1.3.11.tgz#1eb8eb6b3efc921758d6f7ad3d07b250bae53212"
+  integrity sha512-eaplfOveXLl1RCWja7QIke560jUKLprvCXZ446YgQ8vAYB0fXVz3u6AOf7XUmEV9F9PIkNjmfevd1oUPy9qISw==
   dependencies:
     ci-info "2.0.0"
     configstore "^5.0.1"
@@ -6610,21 +6590,20 @@ gatsby-plugin-sass@^2.3.10:
     "@babel/runtime" "^7.10.3"
     sass-loader "^7.3.1"
 
-gatsby-plugin-sharp@^2.6.12:
-  version "2.6.12"
-  resolved "https://registry.yarnpkg.com/gatsby-plugin-sharp/-/gatsby-plugin-sharp-2.6.12.tgz#e3a3b830e58a676dfc7e12e6f94188790aea6483"
-  integrity sha512-cyFjy1KcWvDK7JyWcemMesLIOoyWQQ8Bal133oi29VtLR2A0iwhhm/k8K3AFfYaWeza34edTXsKFVxYhRtRkNw==
+gatsby-plugin-sharp@^2.6.18:
+  version "2.6.18"
+  resolved "https://registry.yarnpkg.com/gatsby-plugin-sharp/-/gatsby-plugin-sharp-2.6.18.tgz#53000b22ee08e829822b1488141df8ae00017567"
+  integrity sha512-DeSPCdwxCsBeJcPxbNtptvn0ta3y/3ABkZm00EtEOeasIjPWDqLDDXi39Q+xGOJVcxsWPs5zinQurJMTV62b8w==
   dependencies:
-    "@babel/runtime" "^7.10.2"
+    "@babel/runtime" "^7.10.3"
     async "^2.6.3"
     bluebird "^3.7.2"
     fs-extra "^8.1.0"
-    gatsby-core-utils "^1.3.6"
+    gatsby-core-utils "^1.3.11"
     got "^8.3.2"
     imagemin "^6.1.0"
     imagemin-mozjpeg "^8.0.0"
     imagemin-pngquant "^6.0.1"
-    imagemin-webp "^5.1.0"
     lodash "^4.17.15"
     mini-svg-data-uri "^1.2.3"
     potrace "^2.1.6"
@@ -7885,15 +7864,6 @@ imagemin-pngquant@^6.0.1:
     is-stream "^1.1.0"
     pngquant-bin "^5.0.0"
 
-imagemin-webp@^5.1.0:
-  version "5.1.0"
-  resolved "https://registry.yarnpkg.com/imagemin-webp/-/imagemin-webp-5.1.0.tgz#ddb1307ad97aff97293c5a600e384e40c07f68a7"
-  integrity sha512-BsPTpobgbDPFBBsI3UflnU/cpIVa15qInEDBcYBw16qI/6XiB4vDF/dGp9l4aM3pfFDDYqR0mANMcKpBD7wbCw==
-  dependencies:
-    cwebp-bin "^5.0.0"
-    exec-buffer "^3.0.0"
-    is-cwebp-readable "^2.0.1"
-
 imagemin@^6.1.0:
   version "6.1.0"
   resolved "https://registry.yarnpkg.com/imagemin/-/imagemin-6.1.0.tgz#62508b465728fea36c03cdc07d915fe2d8cf9e13"
@@ -8310,13 +8280,6 @@ is-color-stop@^1.0.0:
     rgb-regex "^1.0.1"
     rgba-regex "^1.0.0"
 
-is-cwebp-readable@^2.0.1:
-  version "2.0.1"
-  resolved "https://registry.yarnpkg.com/is-cwebp-readable/-/is-cwebp-readable-2.0.1.tgz#afb93b0c0abd0a25101016ae33aea8aedf926d26"
-  integrity sha1-r7k7DAq9CiUQEBauM66ort+SbSY=
-  dependencies:
-    file-type "^4.3.0"
-
 is-data-descriptor@^0.1.4:
   version "0.1.4"
   resolved "https://registry.yarnpkg.com/is-data-descriptor/-/is-data-descriptor-0.1.4.tgz#0b5ee648388e2c860282e793f1856fec3f301b56"