Change the bump-version workflow's schedule (#3512)

* Change the bump-version workflow's schedule

Either I don't understand cron or GitHub doesn't understand cron. It's
not clear which. I think that
https://github.com/bytecodealliance/wasmtime/pull/3511 may have fallen
within our schedule but it was supposed to be on a weekday. Otherwise
https://github.com/bytecodealliance/wasmtime/pull/3499 was certainly
spurious. This commit moves to a simpler "just do it on the same day
each month" and we can manually figure out weekdays and such. Hopefully
this should reduce the number of spurious PRs we're getting to bump
versions.

This also removes the script to force a version bump since I found a
button on the GitHub UI to do the same thing. Additionally I've updated
the patch-release documentation to use this button. Note that this
button takes inputs as well which means we can further automate patch
releases to look even more like normal release process, differing only
in one part of the argument used to trigger the workflow.

* Fix a typo

ci/force-ci-bump-version.sh

@@ -1,16 +0,0 @@
-#!/bin/bash
-
-if [ -z "$PERSONAL_ACCESS_TOKEN" ]; then
-  echo "need to set \$PERSONAL_ACCESS_TOKEN to a github token"
-  exit 1
-fi
-
-exec curl --include --request POST \
-  https://api.github.com/repos/bytecodealliance/wasmtime/actions/workflows/bump-version.yml/dispatches \
-  --header "Authorization: token $PERSONAL_ACCESS_TOKEN" \
-  --data @- << EOF
-{
-  "ref": "main"
-}
-EOF
-