Update actions/setup-go from v2 to v3

Additionally as of v3.1.0 of actions/setup-go there is a go-version
output value to retrieve the version of Go installed by the Action.
This allows us to remove the step to manually retrieve this information
from the Go executable.

.github/workflows/build.yml

@@ -26,14 +26,10 @@ jobs:
           python-version: "3.10"
       # We need the Go version and Go cache location for the actions/cache step,
       # so the Go installation must happen before that.
-      - uses: actions/setup-go@v2
+      - id: setup-go
+        uses: actions/setup-go@v3
         with:
           go-version: "1.16"
-      - name: Store installed Go version
-        id: go-version
-        run: |
-          echo "::set-output name=version::"\
-          "$(go version | sed 's/^go version go\([0-9.]\+\) .*/\1/')"
       - name: Lookup Go cache directory
         id: go-cache
         run: |
@@ -42,7 +38,7 @@ jobs:
         env:
           BASE_CACHE_KEY: "${{ github.job }}-${{ runner.os }}-\
             py${{ steps.setup-python.outputs.python-version }}-\
-            go${{ steps.go-version.outputs.version }}-\
+            go${{ steps.setup-go.outputs.go-version }}-\
             packer${{ steps.setup-env.outputs.packer-version }}-\
             tf${{ steps.setup-env.outputs.terraform-version }}-"
         with: