Update references to reusable actions.

[ianlewis]

Updates all references to internal actions.

This command did the trick (at least for now).

find .github/ -name '*.yaml' -o -name '*.yml' | xargs sed -i 's/uses: slsa-framework\/slsa-github-generator\/\.github\/actions\/\(.*\)@[a-f0-9]*/uses: slsa-framework\/slsa-github-generator\/.github\/actions\/\1@49e648aa7f5f4f88513b6cd54f6b189516184e6b/'

[laurentsimon]

Brilliant, thank you!