Update httparty requirement from ~> 0.16.0 to >= 0.16, < 0.22

Updates the requirements on [httparty](https://github.com/jnunemaker/httparty) to permit the latest version.
- [Release notes](https://github.com/jnunemaker/httparty/releases)
- [Changelog](https://github.com/jnunemaker/httparty/blob/master/Changelog.md)
- [Commits](jnunemaker/httparty@v0.16.4...v0.21.0)

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

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

Gemfile.lock

@@ -8,7 +8,7 @@ PATH
       dragonfly (>= 1.2, < 1.5)
       duktape (~> 2.0.1.1)
       execjs (~> 2.8.1)
-      httparty (~> 0.16.0)
+      httparty (>= 0.16, < 0.22)
       kramdown (~> 2.3.0)
       liquid (~> 4.0.4)
       locomotivecms_common (~> 0.5.0)
@@ -61,8 +61,8 @@ GEM
     haml (5.2.2)
       temple (>= 0.8.0)
       tilt
-    httparty (0.16.4)
-      mime-types (~> 3.0)
+    httparty (0.21.0)
+      mini_mime (>= 1.0.0)
       multi_xml (>= 0.5.2)
     i18n (1.12.0)
       concurrent-ruby (~> 1.0)

locomotivecms_steam.gemspec

@@ -21,7 +21,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'nokogiri',               '~> 1.14.2'
   spec.add_dependency 'sanitize',               '~> 6.0.1'
   spec.add_dependency 'morphine',               '~> 0.1.1'
-  spec.add_dependency 'httparty',               '~> 0.16.0'
+  spec.add_dependency 'httparty',               '>= 0.16', '< 0.22'
   spec.add_dependency 'chronic',                '~> 0.10.2'
   spec.add_dependency 'bcrypt',                 '~> 3.1.11'
   spec.add_dependency 'multi_json',             '~> 1.15.0'