docs(fix): update anchor links in the maintainers guide (#1855)

.github/maintainers_guide.md

@@ -38,7 +38,7 @@ To build reference documentation, in the root of this repo, run `npm run ref-doc
 Reference docs are built by using various open source tools and formats. This includes [API-Extractor](https://api-extractor.com/), [mdast](https://github.com/syntax-tree/mdast), and [Remark](https://github.com/remarkjs/remark). [Read more about the reference docs pipeline](https://github.com/slackapi/node-slack-sdk/pull/831#issue-299509206).
 
 ### 🚀 Releases
-_For beta releases, see [**Beta Releases**](https://github.com/slackapi/node-slack-sdk/blob/main/.github/maintainers_guide.md#beta-releases) section below_
+_For beta releases, see [**Beta Releases**](https://github.com/slackapi/node-slack-sdk/blob/main/.github/maintainers_guide.md#-beta-releases) section below_
 
 Releasing can feel intimidating at first, but rest assured: if you make a mistake, don't fret! npm allows you to unpublish a release within the first 72 hours of publishing (you just won’t be able to use the same version number again). Venture on!
 
@@ -56,7 +56,7 @@ Releasing can feel intimidating at first, but rest assured: if you make a mistak
 
 4. For each package to be released, run `npm run test` to verify that tests are passing and code is free of linting errors.
 
-5. On your new branch, bump the version(s) in `package.json` (see [Versioning and Tags](https://github.com/slackapi/node-slack-sdk/blob/main/.github/maintainers_guide.md#versioning-and-tags))
+5. On your new branch, bump the version(s) in `package.json` (see [Versioning and Tags](https://github.com/slackapi/node-slack-sdk/blob/main/.github/maintainers_guide.md#-versioning-and-tags))
 
     - Make a single commit for the version(s) bump, following the format in: ([Example](https://github.com/slackapi/node-slack-sdk/commit/1503609d79abf035e9e21bad7360e124e4211594))