Bump googleauth from 1.7.0 to 1.8.1

Bumps [googleauth](https://github.com/googleapis/google-auth-library-ruby) from 1.7.0 to 1.8.1.
- [Release notes](https://github.com/googleapis/google-auth-library-ruby/releases)
- [Changelog](https://github.com/googleapis/google-auth-library-ruby/blob/main/CHANGELOG.md)
- [Commits](googleapis/google-auth-library-ruby@googleauth/v1.7.0...googleauth/v1.8.1)

---
updated-dependencies:
- dependency-name: googleauth
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -143,10 +143,9 @@ GEM
     google-protobuf (3.23.4)
     googleapis-common-protos-types (1.7.0)
       google-protobuf (~> 3.14)
-    googleauth (1.7.0)
+    googleauth (1.8.1)
       faraday (>= 0.17.3, < 3.a)
       jwt (>= 1.4, < 3.0)
-      memoist (~> 0.16)
       multi_json (~> 1.11)
       os (>= 0.9, < 2.0)
       signet (>= 0.16, < 2.a)
@@ -207,7 +206,6 @@ GEM
     loofah (2.21.3)
       crass (~> 1.0.2)
       nokogiri (>= 1.12.0)
-    memoist (0.16.2)
     method_source (1.0.0)
     mime-types (3.5.1)
       mime-types-data (~> 3.2015)