- Disabled saving of credential in all checkout actions.

…resence (#111)

* #110 - Introduce GH actions for version tag check and release notes presence
- Switched to use new GH action. Simplified workflow files.

- This file was introduces during deployment experiments.
- It is not needed in current solution as we are deployed like a GH Action to the marketplace.
- No setuptools or similar tooling used.

* #45 - skip-release-notes should allow multiple entires
- Implemented the code.
- Update of docs.

…112)

* #57 - Configurable regex-based Release note detection in the PR body
- Release notes title can be defined by user.
- Release notes title can be defined by regex.

* # Do not fail when unknown placeholder received
- ActionInput now can hold static values.
- Improved unknown placeholder logic for detection and removing of them.

* #117 - Already releases issue are returned from GitHub API
- Added new filtration logic for received issues from GH API. These issues should already be filtered, but there is an error.
- Added new debug message for observing creation time of GH Releases.