Pin to inifile module prior to breaking change

puppetlabs/puppetlabs-inifile@64aaa08#diff-009cf0f832b3fccfa64213c7b2d0fb136df78deec09ac2a21b6d86d729ef3436R63 causes puppet_agent specs to fail on ruby 2.7:

    Evaluation Error: Error while evaluating a Resource Statement, Could not autoload puppet/type/ini_setting: /Users/runner/work/puppetlabs-puppet_agent/puppetlabs-puppet_agent/spec/fixtures/modules/inifile/lib/puppet/type/ini_setting.rb:63: syntax error, unexpected '}'
    ..., not '%{value}'") % { value: }) unless Puppet::Util.absolut...

For now, pin to the most recently released version.

Author: joshcooper

.fixtures.yml

@@ -2,6 +2,8 @@ fixtures:
   repositories:
     stdlib: https://github.com/puppetlabs/puppetlabs-stdlib.git
     apt: https://github.com/puppetlabs/puppetlabs-apt.git
-    inifile: https://github.com/puppetlabs/puppetlabs-inifile.git
+    inifile:
+      repo: https://github.com/puppetlabs/puppetlabs-inifile.git
+      ref: "v6.2.0"
     yumrepo_core: https://github.com/puppetlabs/puppetlabs-yumrepo_core.git
     facts: https://github.com/puppetlabs/puppetlabs-facts.git