GitHub: allow not caching the Golang build cache

This is a tradeoff of disk space (and with that cache size) and
compilation speed. Because we're still running into disk full errors
with the full build cache, we remove it for the cross compile step.
Which means we'll do more work each time.

.github/actions/setup-go/action.yml

@@ -7,6 +7,12 @@ inputs:
   key-prefix:
     description: "A prefix to use for the cache key, to separate cache entries from other workflows"
     required: false
+  use-build-cache: 
+    description: "Whether to use the build cache"
+    required: false
+    # Boolean values aren't supported in the workflow syntax, so we use a
+    # string. To not confuse the value with true/false, we use 'yes' and 'no'.
+    default: 'yes'
 
 runs:
   using: "composite"
@@ -17,7 +23,8 @@ runs:
       with:
         go-version: '${{ inputs.go-version }}'
 
-    - name: go cache
+    - name: go module and build cache
+      if: ${{ inputs.use-build-cache == 'yes' }}
       uses: actions/cache@v3
       with:
         # In order:
@@ -35,6 +42,18 @@ runs:
           ${{ runner.os }}-go-${{ inputs.go-version }}-${{ inputs.key-prefix }}-${{ github.job }}-
           ${{ runner.os }}-go-${{ inputs.go-version }}-${{ inputs.key-prefix }}-
 
+    - name: go module cache
+      if: ${{ inputs.use-build-cache == 'no' }}
+      uses: actions/cache@v3
+      with:
+        # Just the module download cache.
+        path: |
+          ~/go/pkg/mod
+        key: ${{ runner.os }}-go-${{ inputs.go-version }}-${{ inputs.key-prefix }}-no-build-cache-${{ github.job }}-${{ hashFiles('**/go.sum') }}
+        restore-keys: |
+          ${{ runner.os }}-go-${{ inputs.go-version }}-${{ inputs.key-prefix }}-no-build-cache-${{ github.job }}-
+          ${{ runner.os }}-go-${{ inputs.go-version }}-${{ inputs.key-prefix }}-no-build-cache-
+
     - name: set GOPATH
       shell: bash
       run: |

.github/workflows/main.yml

@@ -148,6 +148,7 @@ jobs:
         with:
           go-version: '${{ env.GO_VERSION }}'
           key-prefix: cross-compile
+          use-build-cache: 'no'
 
       - name: build release for all architectures
         run: make release