chore: add bump python version tool

tools/bump-python-version.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+# Bump the version in the setup.py files.
+
+set -u
+
+error() {
+  echo >&2 "error: $*"
+  exit 1
+}
+
+command -v sed > /dev/null || error "sed command not found!"
+
+version="$(cat VERSION)"
+
+for setup_path in */setup.py; do
+  sed --in-place \
+    "s/version=\".*\",/version=\"$version\",/" \
+    "$setup_path"  ||
+    error "could not bump version for $setup_path!"
+done