Add source URL comments to integration test assets

This will make it easier for the maintainers to sync fixes and improvements in either direction between the upstream
"template" assets and their installation in this repository.

Author: per1234

.github/workflows/test-go-integration-task.yml

@@ -1,3 +1,4 @@
+# Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/test-go-integration-task.md
 name: Test Integration
 
 env:

Taskfile.yml

@@ -23,6 +23,7 @@ tasks:
       - task: python:format
       - task: general:format-prettier
 
+  # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/go-task/Taskfile.yml
   go:build:
     desc: Build the Go code
     cmds:
@@ -41,6 +42,7 @@ tasks:
           -coverprofile=coverage_unit.txt \
           {{default .DEFAULT_GO_PACKAGES .GO_PACKAGES}}
 
+  # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/test-go-integration-task/Taskfile.yml
   go:test-integration:
     desc: Run integration tests
     deps: