get collections from repos directly instead of using Ansible Galaxy

As Ansible Galaxy is currently down, switch to using the repos directly.
This avoids reliancy on Ansible Galaxy in the future as well.

requirements.yml

@@ -1,11 +1,13 @@
 collections:
-  # Install a collection from Ansible Galaxy.
-  - name: debops.debops
-    version: ">=3.1.0"
-    source: https://galaxy.ansible.com
-  - name: community.sops
-    version: ">=2.2.4"
-    source: https://galaxy.ansible.com
-  - name: community.docker
-    version: ">=5.0.0"
-    source: https://galaxy.ansible.com
+  # debops.debops
+  - source: https://github.com/debops/debops
+    type: git
+    version: "v3.2.5"
+  # community.sops
+  - source: https://github.com/ansible-collections/community.sops
+    type: git
+    version: "2.2.7"
+  # community.docker
+  - source: https://github.com/ansible-collections/community.docker
+    type: git
+    version: "5.0.5"