[docs] Add cascading metadata

[AaronCrawfis]

Description

Adds cascading metadata so the GitHub links on the docs site work as expected

Issue reference

We strive to have all PR being opened based on an issue, where the problem or feature have been discussed prior to implementation.

Partially fixes https://github.com/dapr/docs/issues/1895

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• [x] Code compiles correctly
• [x] Created/updated tests
• [x] Extended the documentation

[codecov[bot]]

Codecov Report

Merging #582 (8816a0f) into master (18d93c6) will not change coverage. The diff coverage is n/a.

:exclamation: Current head 8816a0f differs from pull request most recent head 3316a17. Consider uploading reports for the commit 3316a17 to get more accurate results

@@           Coverage Diff           @@
##           master     #582   +/-   ##
=======================================
  Coverage   87.14%   87.14%           
=======================================
  Files          73       73           
  Lines        3531     3531           
=======================================
  Hits         3077     3077           
  Misses        454      454