ci: Don't trigger build on certain paths

Makes no sense for updates to issue templates, the funding config and readme.

Also exclude docker folder, as changes will not affect the build until someone builds & pushes updated images.

Do not exclude the LICENSE file however, as it gets packaged in CI runs.

.github/workflows/ci.yml

@@ -4,6 +4,12 @@ on:
   push:
     branches:
       - master
+    paths-ignore:
+      - '.github/ISSUE_TEMPLATE/**'
+      - '.github/FUNDING.yml'
+      - 'docker/**'
+      - 'CONTRIBUTING.md'
+      - 'README.md'
 
 env:
   DOWNLOAD_TOOL: curl -fLOSs --retry 3