Update Gitaly to v1.42.1

What does this MR do?

This MR upgrades Gitaly to v1.42.1. This patch version introduces a fix for the gitaly-wrapper program that is responsible for (re)starting the main Gitaly process. Part of the restart sequence involves detecting the executable path for a running process. This fix ensures that the executable path is correctly identified on both Linux and MacOS.

Incorporates gitaly!1254 (merged)

Related to gitaly!1249 (merged)

Related to gitaly#1661 (closed)

Related to gitlab-org/release/tasks#784 (closed)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team