add auto-formatter GHA triggered by PR (enthought#427)

* add `# fmt: ...` for avoiding redundant format

* add GHA setting

* apply automatic formatter

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

.github/workflows/autofmt.yml

@@ -0,0 +1,27 @@
+on:
+  pull_request:
+    branches: [drop_py2]  # TODO: add `master`
+
+jobs:
+    formatter:
+        name: auto-formatter
+        runs-on: windows-latest
+        steps:
+          - name: Checkout
+            uses: actions/checkout@v3
+          - name: Set up Python
+            uses: actions/setup-python@v4
+            with:
+              python-version: 3.7
+          - name: Install black
+            run: pip install black==22.12.0
+          - name: Format
+            run: python -m black comtypes/.
+          - name: Auto-commit
+            uses: stefanzweifel/git-auto-commit-action@v4
+            with:
+              branch: ${{ github.head_ref }}
+              commit_message: apply automatic formatter
+              commit_user_name: github-actions[bot]
+              commit_user_email: 41898282+github-actions[bot]@users.noreply.github.com
+              commit_author: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

comtypes/GUID.py

@@ -2,12 +2,16 @@
 import sys
 
 if sys.version_info >= (2, 6):
+
     def binary(obj):
         return bytes(obj)
+
 else:
+
     def binary(obj):
         return buffer(obj)
 
+
 if sys.version_info >= (3, 0):
     text_type = str
     base_text_type = str
@@ -31,11 +35,9 @@ def binary(obj):
 # Note: Comparing GUID instances by comparing their buffers
 # is slightly faster than using ole32.IsEqualGUID.
 
+
 class GUID(Structure):
-    _fields_ = [("Data1", DWORD),
-                ("Data2", WORD),
-                ("Data3", WORD),
-                ("Data4", BYTE * 8)]
+    _fields_ = [("Data1", DWORD), ("Data2", WORD), ("Data3", WORD), ("Data4", BYTE * 8)]
 
     def __init__(self, name=None):
         if name is not None:
@@ -50,6 +52,7 @@ def __unicode__(self):
         result = p.value
         _CoTaskMemFree(p)
         return result
+
     __str__ = __unicode__
 
     def __cmp__(self, other):
@@ -61,8 +64,7 @@ def __bool__(self):
         return self != GUID_null
 
     def __eq__(self, other):
-        return isinstance(other, GUID) and \
-               binary(self) == binary(other)
+        return isinstance(other, GUID) and binary(self) == binary(other)
 
     def __hash__(self):
         # We make GUID instances hashable, although they are mutable.
@@ -73,8 +75,7 @@ def copy(self):
 
     @classmethod
     def from_progid(cls, progid):
-        """Get guid from progid, ...
-        """
+        """Get guid from progid, ..."""
         if hasattr(progid, "_reg_clsid_"):
             progid = progid._reg_clsid_
         if isinstance(progid, cls):