fix: Pin bash shebang

Author: marverix

action.yaml

@@ -74,3 +74,10 @@ runs:
       run: |
         curl -sL https://raw.githubusercontent.com/marverix/gah/refs/tags/$tag/gah -o "$GAH_INSTALL_DIR/gah"
         chmod +x "$GAH_INSTALL_DIR/gah"
+
+    - name: Pin bash shebang
+      shell: bash
+      run: |
+        bash_location=$(which bash)
+        bash_location="#\!${bash_location}"
+        sed -i "1 s|.*|$bash_location|" "$GAH_INSTALL_DIR/gah"