build: 🔨 use bash in justfile so CI doesn't need zsh (#149)

# Description

Moved from #134.

Closes #128

No review needed.

Author: lwjohnst86

justfile

@@ -32,14 +32,15 @@ update-template:
 
 # Check the commit messages on the current branch that are not on the main branch
 check-commits:
-  #!/bin/zsh
+  #!/usr/bin/env bash
   branch_name=$(git rev-parse --abbrev-ref HEAD)
   number_of_commits=$(git rev-list --count HEAD ^main)
   if [[ ${branch_name} != "main" && ${number_of_commits} -gt 0 ]]
   then
+    # If issue happens, try `uv tool update-shell`
     uvx --from commitizen cz check --rev-range main..HEAD
   else
-    echo "On `main` or current branch doesn't have any commits."
+    echo "On 'main' or current branch doesn't have any commits."
   fi
 
 # Check for spelling errors in files
@@ -48,7 +49,7 @@ check-spelling:
 
 # Test and check that a Python package can be created from the template
 test is_seedcase_project:
-  #!/bin/zsh
+  #!/usr/bin/env bash
   test_name="test-python-package"
   test_dir="$(pwd)/_temp/{{ is_seedcase_project }}/$test_name"
   template_dir="$(pwd)"
@@ -103,7 +104,6 @@ test is_seedcase_project:
 
 # Clean up any leftover and temporary build files
 cleanup:
-  #!/bin/zsh
   rm -rf _temp
 
 # Build the website using Quarto