pullapprove: remove it

We are moving off pullapprove. Remove its config file.

Fixes: #228

Signed-off-by: Graham Whaley <graham.whaley@intel.com>

.pullapprove.yml

@@ -1,43 +0,0 @@
-version: 2
-
-requirements:
-  signed_off_by:
-    required: true
-
-# Disallow approval of PRs still under development
-always_pending:
-  title_regex: '(WIP|RFC)'
-  labels:
-    - do-not-merge
-    - wip
-    - rfc
-  explanation: 'Work in progress - do not merge'
-
-group_defaults:
-  approve_by_comment:
-    enabled: true
-    approve_regex: '^(LGTM|lgtm|Approved|\+1|:\+1:)'
-    reject_regex: '^(Rejected|-1|:-1:)'
-  reset_on_push:
-    enabled: false
-  reset_on_reopened:
-    enabled: false
-  author_approval:
-    ignored: true
-
-groups:
-  approvers:
-    required: 2
-    teams:
-      - builder
-
-  documentation:
-    required: 1
-    teams:
-      - documentation
-    conditions:
-      files:
-        include:
-          - "*.md"
-        exclude:
-          - "vendor/*"