contrib: drop incr_version script

This isn't used anymore.

contrib/_incr_version

@@ -1,21 +0,0 @@
-#!/bin/sh -eu
-old_version="$1"
-new_version="$2"
-
-if [ "$new_version" != "${new_version#v}" ]
-then
-	echo "Error: The new version shouldn't be prefixed with a \"v\"." >&2
-	exit 1
-fi
-
-sed -i meson.build -e "s/^	version: .*#release_version/	version: '$new_version', #release_version/g"
-
-printf "Minimum wlroots version? "
-read wlr_version_min
-printf "Maximum wlroots version? "
-read wlr_version_max
-
-sed -i meson.build -e "s/wlroots_version =.*/wlroots_version = ['>=$wlr_version_min', '<$wlr_version_max']/"
-
-git add meson.build
-git commit -m "Update version to $new_version"