feat(ConventionalCommitsCz): allow to override defaults from config

[amitlevy21]

Before fixing tests and adding extra ones, I would like to receive partial feedback about my changes to see if this aligns with the desired code changes by maintainers.

As addressed on #535, when using customize commitizen, if we want to customize a small attribute, we need to redefine all commitizens options to make our custom class work.

For example:

diff --git a/cz.yaml b/cz.yaml
index f2e19a9..302e961 100644
--- a/cz.yaml
+++ b/cz.yaml
@@ -1,6 +1,18 @@
 commitizen:
   annotated_tag: true
   bump_message: 'bump: $current_version -> $new_version [skip ci]'
-  name: cz_conventional_commits
+  name: cz_customize
   update_changelog_on_bump: true
   version: 0.11.0
+
+  customize:
+    bump_pattern: '^(fix|feat|docs|style|refactor|test|build|ci)'
+    bump_map:
+      fix: PATCH
+      feat: PATCH
+      docs: PATCH
+      style: PATCH
+      refactor: PATCH
+      test: PATCH
+      build: PATCH
+      ci: PATCH
diff --git a/t b/t
new file mode 100644
index 0000000..e69de29
diff --git a/t2 b/t2
new file mode 100644
index 0000000..e69de29

making the following change on a repo would cause an unexpected behavior:

+ bash -c cz commit

Traceback (most recent call last):
  File "/home/amit/.local/bin/cz", line 8, in <module>
    sys.exit(main())
  File "/home/amit/.local/lib/python3.10/site-packages/commitizen/cli.py", line 382, in main
    args.func(conf, vars(args))()
  File "/home/amit/.local/lib/python3.10/site-packages/commitizen/commands/commit.py", line 74, in __call__
    m = self.prompt_commit_questions()
  File "/home/amit/.local/lib/python3.10/site-packages/commitizen/commands/commit.py", line 49, in prompt_commit_questions
    for question in filter(lambda q: q["type"] == "list", questions):
  File "/home/amit/.local/lib/python3.10/site-packages/commitizen/commands/commit.py", line 49, in <lambda>
    for question in filter(lambda q: q["type"] == "list", questions):
KeyError: 'type'

From my best understanding, this error happens because I didn't defined question section in config, though I'm ok with using ConventionalCommitsCz default ones.

This commit extends ConventionalCommitsCz to read from config and fallbacks to defaults if some are not provided.

By adding this change, potentially customize commitizen can be deprecated.

A warning message will be printed when using cz_customize

Closes #535.

Description

Checklist

• [x] Add test cases to all the changes you introduce
• [x] Run ./scripts/format and ./scripts/test locally to ensure this change passes linter check and test
• [x] Test the changes on the local machine manually
• [ ] Update the documentation for the changes

Expected behavior

Steps to Test This Pull Request

Additional context

[amitlevy21]

@Lee-W Hi, made some changes and fixed tests, Can you take another look?