Merge #2903: [GA] Link Boost 1.76 regardless of pre-existing version

0c49798 [GA] Link Boost 1.76 regardless of pre-existing version (Fuzzbawls)

Pull request description:

  GA's macos-11 runner images have been inconsistent in their inclusion of
   a pre-installed version of the Boost library, and trying to gracefully
   unlink a non-existent package results in an error.

  Skip the unlink step and just force overwrite linking boost 1.76.

ACKs for top commit: 0c49798
  Liquid369:
    tACK 0c49798
  Duddino:
    utACK 0c49798

Tree-SHA512: 9fbc397a447be7a4cabbd28473ce909a555a7fb0dff9197ff409e41bc404424ccd5c914ed835ec21bfc71d3f3916e3f8e267f3f52a9b01b099386d20645a43b8

.github/workflows/build-and-test.yml

@@ -115,10 +115,10 @@ jobs:
           fi
           if [[ ${{ matrix.config.os }} = macos* ]]; then
             brew install "$APT_BASE" ${{ matrix.config.packages }}
-            # GA's macOS 11 image has recently started leaking the pre-installed boost libraries
-            # despite us setting an explicit path. Temp workaround is to unlink the pre-installed version
+            # GA's macOS 11 image is inconsistent as to if it includes a pre-installed version of boost. Force linking
+            # to the specified version (1.76), which will overwrite the symlinks to a pre-existing version if it exists.
             if [ "${{ matrix.config.os }}" = "macos-11" ]; then
-              brew unlink boost && brew link --overwrite -f boost@1.76
+              brew link --overwrite -f boost@1.76
             fi
           fi