.fixtures.yml: Migrate to git

it's best practice to use git branches in unit tests, not the latest
forge releases. This approach tries to catch breaking changes or
regressions in depenencies before they are released.

.fixtures.yml

@@ -1,32 +1,12 @@
+---
 fixtures:
-  forge_modules:
-    epel:
-      repo: "puppet/epel"
-      ref: "3.0.1"
-    stdlib:
-      repo: "puppetlabs/stdlib"
-      ref: "9.3.0"
-    mysql:
-      repo: "puppetlabs/mysql"
-      ref: "15.0.0"
-    postgresql:
-      repo: "puppetlabs/postgresql"
-      ref: "9.1.0"
-    concat:
-      repo: "puppetlabs/concat"
-      ref: "5.3.0"
-    apt:
-      repo: "puppetlabs/apt"
-      ref: "6.3.0"
-    yumrepo:
-      repo: "puppetlabs/yumrepo_core"
-      puppet_version: ">= 6.0.0"
-      ref: "1.0.3"
-    augeas:
-      repo: "puppetlabs/augeas_core"
-      puppet_version: ">= 6.0.0"
-      ref: "1.0.4"
   repositories:
-    systemd: 'https://github.com/voxpupuli/puppet-systemd'
-  symlinks:
-    powerdns: "#{source_dir}"
+    concat: https://github.com/puppetlabs/puppetlabs-concat.git
+    stdlib: https://github.com/puppetlabs/puppetlabs-stdlib.git
+    epel: https://github.com/voxpupuli/puppet-epel.git
+    mysql: https://github.com/puppetlabs/puppetlabs-mysql.git
+    postgresql: https://github.com/puppetlabs/puppetlabs-postgresql.git
+    apt: https://github.com/puppetlabs/puppetlabs-apt.git
+    systemd: https://github.com/voxpupuli/puppet-systemd
+    yumrepo_core: https://github.com/puppetlabs/puppetlabs-yumrepo_core.git
+    augeas_core: https://github.com/puppetlabs/puppetlabs-augeas_core.git