Fix unterminated string in Dependabot update-types example

The final sequence item in the combined `update-types`/`dependency-type`
example was missing its closing double quote, so the block does not parse
as YAML. The same string appears correctly quoted four other times in this
file.

The block is tagged `yaml copy`, so the copy button offers a dependabot.yml
that Dependabot would reject.

Author: SurefireStudios

content/code-security/how-tos/secure-your-supply-chain/manage-your-dependency-security/controlling-dependencies-updated.md

@@ -212,7 +212,7 @@ Here are some examples showing how `update-types` can be used with `allow`.
          - dependency-type: "development"
            update-types:
              - "version-update:semver-minor"
-             - "version-update:semver-patch
+             - "version-update:semver-patch"
    ```
 
   In this example, production dependencies will only receive patch updates, while development dependencies will receive both minor and patch updates.