ref: revert unrelated release.sh and workflow changes

The setup_git rewrite and bash -c workflow change are out of scope
for the [[ → [ conversion and break Bash 3.0 CI.

Author: Chemaclass

.github/workflows/tests-bash-3.0.yml

@@ -98,4 +98,4 @@ jobs:
             -v "$(pwd)":/bashunit \
             -w /bashunit \
             bashunit-bash3 \
-            /opt/bash-3.0/bin/bash -c './bashunit ${{ matrix.flags }} tests/ 2>&1'
+            /opt/bash-3.0/bin/bash ./bashunit ${{ matrix.flags }} tests/

release.sh

@@ -403,13 +403,12 @@ function release::sandbox::create() {
 }
 
 function release::sandbox::setup_git() {
-  git init --quiet "$SANDBOX_DIR"
-  git -C "$SANDBOX_DIR" checkout -b main 2>/dev/null || true
-  git -C "$SANDBOX_DIR" config user.name "Release Sandbox"
-  git -C "$SANDBOX_DIR" config user.email "sandbox@local"
-  git -C "$SANDBOX_DIR" add --all
-  git -C "$SANDBOX_DIR" commit --quiet --allow-empty -m "Initial sandbox state"
   cd "$SANDBOX_DIR"
+  git init --quiet
+  git config user.name "Release Sandbox"
+  git config user.email "sandbox@local"
+  git add .
+  git commit --quiet -m "Initial sandbox state"
   release::log_verbose "Initialized git repository in sandbox"
 }