Add script to automate some of release process.

scripts/version-bump.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/bash
+
+set -eu
+
+# This script automates the "Version bump" section
+
+version="$1"
+
+if [[ -z $version ]]; then
+  echo "Usage: must supply version as first argument" >&2
+  exit 1
+fi
+
+git switch -C "release-$version"
+sed -i -e "0,/^\[badges/{s/^version =.*/version = \"$version\"/}" Cargo.toml
+
+msrv="$(grep -F rust-version Cargo.toml | sed -e 's/^rust-version= "\(.*\)"/\1/')"
+
+sed -i -e "s/Note that rust version \*[0-9.]+\* or later/Note that rust version *$msrv* or later/" README.md
+
+sed -i -e "s/^# Upcoming release/# $version/" CHANGELOG.md
+