enhancement(deps): cut a release when unstructured libs are bumped

[awalker4]

• Set dependabot to run daily and only pick up unstructured changes
• Add version-increment.sh to add a line to the changelog and cut a release
• Add a new action, triggered off dependabot prs, to run version-increment on pr branch

I may have the syntax a bit off, so we'll see what happens when dependabot runs next.

[awalker4]

Got it to work!! https://github.com/Unstructured-IO/unstructured-api/pull/228/files