Fix 1.0.0-rc.1 extensions and 1.0.0-beta.1 schema links

[duckontheweb]

Related Issue(s):

• Change how validating 1.0.0-rc.1 extensions are handled  #333
• Provide validation support for 1.0.0-beta.1 #334

Description:

Builds off of #336 by fixing an issue with examples-info.csv, rebasing, and squashing commites. Thanks @jonhealy1!

PR Checklist:

• Code is formatted (run pre-commit run --all-files)
• Tests pass (run scripts/test)
• Documentation has been updated to reflect changes, if applicable
• This PR maintains or improves overall codebase code coverage.
• Changes are added to the CHANGELOG. See the docs for information about adding to the changelog.

[codecov-commenter]

Codecov Report

Merging #455 (7b3acf9) into main (6937607) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #455   +/-   ##
=======================================
  Coverage   91.48%   91.48%           
=======================================
  Files          40       40           
  Lines        5240     5240           
=======================================
  Hits         4794     4794           
  Misses        446      446           

Impacted Files	Coverage Δ
pystac/validation/schema_uri_map.py	86.84% <ø> (ø)
pystac/validation/__init__.py	84.61% <100.00%> (ø)

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[lossyrob]

Should drop the empty README at tests/data-files/examples/1.0.0-RC1/README.md

Otherwise GTG