Add bump script.

bump.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+latest=$(git describe --tags --abbrev=0 2>/dev/null || echo "v0.0.0")
+IFS='.' read -r major minor patch <<< "${latest#v}"
+
+case ${1:-patch} in
+    major) new="v$((major+1)).0.0" ;;
+    minor) new="v${major}.$((minor+1)).0" ;;
+    patch) new="v${major}.${minor}.$((patch+1))" ;;
+    *) echo "Usage: bump.sh [major|minor|patch]" >&2; exit 1 ;;
+esac
+
+git tag -a "$new"
+