Use standard version of Go in "Check Website" workflow

Go 1.16 is now used for all development of this project. This is the last remaining component of the project
infrastructure left specifiying Go 1.14.

Author: per1234

.github/workflows/check-mkdocs-task.yml

@@ -3,7 +3,7 @@ name: Check Website
 
 env:
   # See: https://github.com/actions/setup-go/tree/v2#readme
-  GO_VERSION: "1.14"
+  GO_VERSION: "1.16"
   # See: https://github.com/actions/setup-python/tree/v2#available-versions-of-python
   PYTHON_VERSION: "3.9"