Update rexml requirement from = 3.2.5 to = 3.2.8

Updates the requirements on [rexml](https://github.com/ruby/rexml) to permit the latest version.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.2.5...v3.2.8)

---
updated-dependencies:
- dependency-name: rexml
  dependency-type: direct:production
...

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

Gemfile.lock

@@ -4,7 +4,7 @@ PATH
     omniauth-nextcloud (0.2.2)
       omniauth (= 2.0.4)
       omniauth-oauth2 (= 1.7.2)
-      rexml (= 3.2.5)
+      rexml (= 3.2.8)
 
 GEM
   remote: https://rubygems.org/
@@ -41,7 +41,8 @@ GEM
     rainbow (3.0.0)
     rake (13.0.6)
     regexp_parser (2.1.1)
-    rexml (3.2.5)
+    rexml (3.2.8)
+      strscan (>= 3.0.9)
     rspec (3.10.0)
       rspec-core (~> 3.10.0)
       rspec-expectations (~> 3.10.0)
@@ -68,6 +69,7 @@ GEM
       parser (>= 3.0.1.1)
     ruby-progressbar (1.11.0)
     ruby2_keywords (0.0.5)
+    strscan (3.1.0)
     unicode-display_width (2.1.0)
 
 PLATFORMS

omniauth-nextcloud.gemspec

@@ -30,7 +30,7 @@ Gem::Specification.new do |spec|
   # Uncomment to register a new dependency of your gem
   spec.add_dependency "omniauth", "2.0.4"
   spec.add_dependency "omniauth-oauth2", "1.7.2"
-  spec.add_dependency "rexml", "3.2.5"
+  spec.add_dependency "rexml", "3.2.8"
 
   # For more information and examples about making a new gem, checkout our
   # guide at: https://bundler.io/guides/creating_gem.html