Log POST failures instead of failing entire action (#1625)

Previously, website issues would cause the entire action to fail, and
users would complain. Now, failures are logged as warnings using
GitHub's workflow command syntax:

https://docs.github.com/actions/reference/workflows-and-actions/workflow-commands

Afterwards, the rest of the workflow job, such as uploading to the code
scanning dashboard, can continue.

Signed-off-by: Spencer Schrock <sschrock@google.com>

Author: spencerschrock

signing/signing.go

@@ -166,7 +166,9 @@ func (s *Signing) ProcessSignature(jsonPayload []byte, repoName, repoRef string)
 
 	// retries failed
 	if err != nil {
-		return fmt.Errorf("error sending scorecard results to webapp: %w", err)
+		log.Printf("::warning::Unable to POST scorecard results to webapp: %v. "+
+			"If this issue persists, check the repo issues for more information.\n", err)
+		return nil
 	}
 
 	return nil

signing/signing_test.go

@@ -95,7 +95,7 @@ func TestProcessSignature(t *testing.T) {
 			name:        "post failed",
 			status:      http.StatusBadRequest,
 			payloadPath: "testdata/results.json",
-			wantErr:     true,
+			wantErr:     false,
 		},
 	}
 	// use smaller backoffs for the test so they run faster
@@ -192,7 +192,7 @@ func TestProcessSignature_retries(t *testing.T) {
 			name:          "retry limit exceeded",
 			nFailures:     4,
 			wantNRequests: 3,
-			wantErr:       true,
+			wantErr:       false,
 		},
 	}
 	// use smaller backoffs for the test so they run faster