Bump webmock from 3.7.1 to 3.18.1

Bumps [webmock](https://github.com/bblimke/webmock) from 3.7.1 to 3.18.1.
- [Release notes](https://github.com/bblimke/webmock/releases)
- [Changelog](https://github.com/bblimke/webmock/blob/master/CHANGELOG.md)
- [Commits](bblimke/webmock@v3.7.1...v3.18.1)

---
updated-dependencies:
- dependency-name: webmock
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Gemfile.lock

@@ -5,15 +5,15 @@ GEM
       public_suffix (>= 2.0.2, < 5.0)
     bugsnag (5.2.0)
     coderay (1.1.2)
-    crack (0.4.3)
-      safe_yaml (~> 1.0.0)
+    crack (0.4.5)
+      rexml
     diff-lcs (1.2.5)
     docker_registry2 (1.8.0)
       rest-client (>= 1.8.0)
     domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
     dotenv (2.1.2)
-    hashdiff (1.0.0)
+    hashdiff (1.0.1)
     http-cookie (1.0.3)
       domain_name (~> 0.5)
     method_source (0.8.2)
@@ -28,7 +28,7 @@ GEM
       coderay (~> 1.1.0)
       method_source (~> 0.8.1)
       slop (~> 3.4)
-    public_suffix (4.0.6)
+    public_suffix (4.0.7)
     puma (5.6.4)
       nio4r (~> 2.0)
     rack (2.2.3)
@@ -40,6 +40,7 @@ GEM
       http-cookie (>= 1.0.2, < 2.0)
       mime-types (>= 1.16, < 4.0)
       netrc (~> 0.8)
+    rexml (3.2.5)
     rspec (3.5.0)
       rspec-core (~> 3.5.0)
       rspec-expectations (~> 3.5.0)
@@ -54,7 +55,6 @@ GEM
       rspec-support (~> 3.5.0)
     rspec-support (3.5.0)
     ruby2_keywords (0.0.2)
-    safe_yaml (1.0.5)
     sinatra (2.0.8.1)
       mustermann (~> 1.0)
       rack (~> 2.0)
@@ -66,8 +66,8 @@ GEM
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.6)
-    webmock (3.7.1)
-      addressable (>= 2.3.6)
+    webmock (3.18.1)
+      addressable (>= 2.8.0)
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)