cicd: use extracted git archive

I thought that docker could use a tarball context, but it can only do
this for a URL, for some reason. This copies the dance that the release
build step does.

Signed-off-by: Hank Donnay <hdonnay@redhat.com>

.github/script/nightly-module.sh

@@ -12,4 +12,4 @@ git diff
 test -d vendor && rm -rf vendor
 go mod tidy
 go mod vendor
-printf '::set-output name=clair_version::%s\n' "$(git describe --tags --always --dirty --match 'v4.*')"
+echo "clair_version=$(git describe --tags --always --dirty --match 'v4.*')" >> "$GITHUB_OUTPUT"

.github/workflows/nightly.yml

@@ -75,14 +75,17 @@ jobs:
           password: ${{ secrets.QUAY_TOKEN }}
       - name: Export
         # This exports the current state of the main branch, and appends our modified go module files.
-        run: 'git archive -o clair.tar --add-file=go.mod --add-file=go.sum "main"'
+        run: |
+          mkdir "${{ runner.temp }}/build"
+          git archive --add-file=go.mod --add-file=go.sum origin/main |
+            tar -x -C "${{ runner.temp }}/build"
       - uses: docker/build-push-action@v3
         with:
           build-args: |
             GO_VERSION=${{ env.GO_VERSION }}
           cache-from: type=gha
           cache-to: type=gha,mode=max
-          context: clair.tar
+          context: ${{ runner.temp }}/build
           platforms: linux/amd64,linux/arm64
           push: ${{ steps.setup.outputs.push && steps.novelty.outputs.cache-hit != 'true' }}
           tags: |