Bump external/Catch2 from `18c5866` to `0e176c3` (#826)

Bumps [external/Catch2](https://github.com/catchorg/Catch2) from `18c5866` to `0e176c3`.
- [Release notes](https://github.com/catchorg/Catch2/releases)
- [Commits](18c58667d7...0e176c318b)

---
updated-dependencies:
- dependency-name: external/Catch2
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Alan Jowett <alanjo@microsoft.com>

external/Catch2

@@ -1 +1 @@
-Subproject commit 18c58667d780bfdc82d0e52d6ac6afc462e28f47
+Subproject commit 0e176c318bf309aaa4acd8686a82517fda7b859a