Bump rexml from 3.2.6 to 3.2.8 (#717)

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.6 to 3.2.8.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.2.6...v3.2.8)

---
updated-dependencies:
- dependency-name: rexml
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -116,7 +116,7 @@ GEM
       xcodeproj (>= 1.13.0, < 2.0.0)
       xcpretty (~> 0.3.0)
       xcpretty-travis-formatter (>= 0.0.3)
-    ffi (1.16.3-x64-mingw-ucrt)
+    ffi (1.16.3)
     gh_inspector (1.1.3)
     google-apis-androidpublisher_v3 (0.54.0)
       google-apis-core (>= 0.11.0, < 2.a)
@@ -179,7 +179,8 @@ GEM
       trailblazer-option (>= 0.1.1, < 0.2.0)
       uber (< 0.2.0)
     retriable (3.1.2)
-    rexml (3.2.6)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rouge (2.0.7)
     ruby2_keywords (0.0.5)
     rubyzip (2.3.2)
@@ -193,6 +194,7 @@ GEM
       CFPropertyList
       naturally
     sshkey (3.0.0)
+    strscan (3.1.0)
     terminal-notifier (2.0.0)
     terminal-table (3.0.2)
       unicode-display_width (>= 1.1.1, < 3)
@@ -218,7 +220,6 @@ GEM
 
 PLATFORMS
   x86_64-linux
-  x86_64-darwin-20
 
 DEPENDENCIES
   fastlane