feat(git): add checkout git branch to gitf (#47)

Reviewed-on: https://codeberg.org/vlw/dotfiles/pulls/47

.bash_aliases

@@ -83,6 +83,18 @@ gitf () {
             gitf w
             ;;
 
+        # Checkout [and create] a git branch (defaults to "master")
+        "b")
+            local branch="${2:-master}"
+
+            if git show-ref --verify --quiet refs/heads/"$branch"; then
+                git checkout $branch
+                return 0
+            fi
+
+            git checkout -b $branch
+            ;;
+
         # Clear local branches that have no upstream on remote (cleanup)
         "c")
             git fetch -p && git branch -vv | awk '/: gone]/{print $1}' | xargs git branch -D