fix: pact_broker/Gemfile.lock to reduce vulnerabilities (#79)

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-2620374
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-2630623
- https://snyk.io/vuln/SNYK-RUBY-NOKOGIRI-2630898

pact_broker/Gemfile.lock

@@ -68,7 +68,7 @@ GEM
       ruby2_keywords (~> 0.0.1)
     mysql2 (0.5.3)
     nio4r (2.5.8)
-    nokogiri (1.13.3)
+    nokogiri (1.13.4)
       mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     pact-support (1.17.0)
@@ -129,15 +129,15 @@ GEM
       rack (>= 1.4)
     roar (1.1.1)
       representable (~> 3.0)
-    ruby-next-core (0.15.0)
+    ruby-next-core (0.15.1)
     ruby2_keywords (0.0.5)
     sanitize (6.0.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.12.0)
     semantic_logger (4.10.0)
       concurrent-ruby (~> 1.0)
     semver2 (3.4.2)
-    sequel (5.54.0)
+    sequel (5.55.0)
     sinatra (2.2.0)
       mustermann (~> 1.0)
       rack (~> 2.2)