ci: Define default shell for all workflows (#47883)

GitHub allows defining a default shell for all jobs on the workflow
level, which we did not use before, yet practically did when it comes
down to our usage of `named::bash`. Since this makes stuff quite
verbose, I decided on using the defaults instead so the workflows become
somewhat easier to audit when reading the generated files.

Powershell steps continue to use Powershell, only the default for bash
scripts was modified.


Release Notes:

- N/A

.github/workflows/bump_patch_version.yml

@@ -46,7 +46,6 @@ jobs:
         git commit -am "Bump to $output for @$GITHUB_ACTOR"
         git tag "v${output}${tag_suffix}"
         git push origin HEAD "v${output}${tag_suffix}"
-      shell: bash -euxo pipefail {0}
       env:
         GIT_COMMITTER_NAME: Zed Zippy
         GIT_COMMITTER_EMAIL: 234243425+zed-zippy[bot]@users.noreply.github.com
@@ -56,3 +55,6 @@ jobs:
 concurrency:
   group: ${{ github.workflow }}-${{ inputs.branch }}
   cancel-in-progress: true
+defaults:
+  run:
+    shell: bash -euxo pipefail {0}