misc: Update instructions for AppVeyor

appveyor.yml

@@ -2,25 +2,13 @@ clone_folder: c:\projects\go\src\github.com\tus\tusd
 
 environment:
   GOPATH: c:\projects\go
-  GO15VENDOREXPERIMENT: 1
-
-install:
-  - git submodule update --init --recursive
+  GO111MODULE: on
 
 build_script:
   - set PATH=%GOPATH%\bin;%PATH%
   - go env
   - go version
-  - go get ./s3store
-  - go get ./consullocker
-  - go get ./prometheuscollector
-  - go get github.com/hashicorp/consul
 
 test_script:
-  - go test .
-  - go test ./filestore
-  - go test ./limitedstore
-  - go test ./memorylocker
-  - go test ./s3store
-  - go vet ./prometheuscollector
-  - go test ./gcsstore
+  - go test ./pkg/...
+  - go vet ./pkg/...