.pullapprove.yml: List project maintainers separately

This repository is managed by the union of all OCI Project
maintainers.  To avoid having a few active maintainers from one
project driving the template in ways that other projects don't
support, require at least two approvals from each project.  This will
slow down acceptance a bit, but many maintainers belong to multiple
projects (and their votes will count for each group [1]), so you won't
need 12 separate maintainers voting to get a single project-template
PR across the line.

Also update from config format v1 to v2 [1,2].

[1]: http://docs.pullapprove.com/migrating-to-v2/
[2]: http://docs.pullapprove.com/

Signed-off-by: W. Trevor King <[email protected]>

Author: wking

.pullapprove.yml

@@ -1,13 +1,36 @@
-approve_by_comment: true
-approve_regex: ^LGTM
-reject_regex: ^Rejected
-reset_on_push: true
-author_approval: ignored
-signed_off_by:
-  required: true
-reviewers:
-  teams:
-  - tdc-maintainers
-  - admins
-  name: default
+version: 2
+
+requirements:
+  signed_off_by:
+    required: true
+
+group_defaults:
   required: 2
+  approve_by_comment:
+    enabled: true
+    approve_regex: ^LGTM
+    reject_regex: ^Rejected
+  reset_on_push:
+    enabled: true
+  author_approval:
+    ignored: true
+
+groups:
+  image-spec:
+    teams:
+      - image-spec-maintainers
+  image-tools:
+    teams:
+      - image-tools-maintainers
+  go-digest:
+    teams:
+      - go-digest-maintainers
+  runc:
+    teams:
+      - runc-maintainers
+  runtime-spec:
+    teams:
+      - runtime-spec-maintainers
+  runtime-tools:
+    teams:
+      - runtime-tools-maintainers