[misc] misc/make_changelog.py for automatically generating changelo…

…gs (#679)

* misc/make_changelog.py

* [skip ci] make_changelog

* [skip ci] format

misc/make_changelog.py

@@ -0,0 +1,66 @@
+from git import Repo
+
+# Usage: python3 misc/make_changelog.py 0.5.9
+
+import sys
+
+ver = sys.argv[1]
+
+g = Repo('.')
+commits = list(g.iter_commits('master', max_count=200))
+begin, end = -1, 0
+
+
+def format(c):
+    return f'{c.summary} (by **{c.author}**)'
+
+
+print('Notable changes:')
+
+notable_changes = {}
+all_changes = []
+
+details = {
+    'cpu': 'CPU backends',
+    'cuda': 'CUDA backend',
+    'doc': 'Documentation',
+    'infra': 'Infrastructure',
+    'ir': 'Intermediate Representation',
+    'lang': 'Language and Syntax',
+    'metal': 'Metal backend',
+    'misc': 'Miscellaneous',
+    'opt': 'Optimization',
+}
+
+print(f'-(, 2020) v{ver} released')
+for i, c in enumerate(commits):
+    s = format(c)
+    if s.startswith('[release]'):
+        break
+    tags = []
+    while s[0] == '[':
+        r = s.find(']')
+        tag = s[1:r]
+        tags.append(tag)
+        s = s[r + 1:]
+    for tag in tags:
+        if tag[0].isupper():
+            tag = tag.lower()
+            if tag not in notable_changes:
+                notable_changes[tag] = []
+            notable_changes[tag].append(s)
+    if s.startswith('[release]'):
+        break
+    all_changes.append(format(c))
+
+for tag in sorted(notable_changes.keys()):
+    print(f'   - **{details[tag]}**')
+    for item in notable_changes[tag]:
+        print(f'      -{item}')
+print(
+    f'      - [Full log](https://github.com/taichi-dev/taichi/releases/tag/{ver})'
+)
+
+print('Full changelog:')
+for c in all_changes:
+    print(f'   - {c}')