Suppress SHA1_RSA failures, these only occur in tests.

We should fix this with new testdata but we're blocked on an
upstream change.

Signed-off-by: Dan Lorenc <dlorenc@chainguard.dev>

.github/workflows/tests.yaml

@@ -60,6 +60,9 @@ jobs:
           go-version: ${{ env.GO_VERSION }}
           check-latest: true
       - name: Run Go tests
+        env:
+          # See #2091 for the issue describing this temp workaround.
+          GODEBUG: x509sha1=1
         run: go test -covermode atomic -coverprofile coverage.txt $(go list ./... | grep -v third_party/)
       - name: Upload Coverage Report
         uses: codecov/codecov-action@81cd2dc8148241f03f5839d295e000b8f761e378 # v2.1.0