ci: fix up some build breakages

Fix a bad check on pulling master through the proxy. We need to use go
get -d. Tested locally.

Also restrict our generation to the exact Go 1.14.x version specified in
the matrix, and do not run on Windows (it's flaky for some reason).

Unfortunately the trybot run for this change will fail because the tests
triggered by the runtrybot use the workflow files from master on GitHub.
So we will need to submit the CL to see the results.

Change-Id: I7fb0bac3a2971b349d35a2ef15aec05fe921a48c
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/6065
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

.github/workflows/test.yml

@@ -23,7 +23,7 @@ jobs:
     runs-on: ${{ matrix.platform }}
     steps:
     - name: Install Go
-      uses: actions/setup-go@v1
+      uses: actions/setup-go@v2
       with:
         go-version: ${{ matrix.go-version }}
 
@@ -39,6 +39,9 @@ jobs:
           ${{ runner.os }}-${{ matrix.go-version }}-go-
 
     - name: Generate
+      # The Go version corresponds to the precise 1.14.x version specified in
+      # the matrix. Skip windows for now until we work out why re-gen is flaky
+      if: matrix.go-version == "1.14.3" && matrix.platform != "windows-latest"
       run: go generate ./...
 
     - name: Test
@@ -58,4 +61,4 @@ jobs:
         v=$(git rev-parse HEAD)
         cd $(mktemp -d)
         go mod init mod.com
-        GOPROXY=https://proxy.golang.org go get cuelang.org/go@$v
+        GOPROXY=https://proxy.golang.org go get -d cuelang.org/go@$v

.github/workflows/test_dispatch.yml

@@ -51,6 +51,9 @@ jobs:
           ${{ runner.os }}-${{ matrix.go-version }}-go-
 
     - name: Generate
+      # The Go version corresponds to the precise 1.14.x version specified in
+      # the matrix. Skip windows for now until we work out why re-gen is flaky
+      if: matrix.go-version == "1.14.3" && matrix.platform != "windows-latest"
       run: go generate ./...
 
     - name: Test