Cache

[kateinoigakukun]

IBLinter checks whole files every time but there are many unnecessary processes when most of them are not changed.

This PR adds lint cache for each IB file. In my project, IBLinter took 7 sec every time but this change reduced it to 2 sec when there is cache.

[kateinoigakukun]

@phimage Your understanding is almost correct. As you said, we should re-check if IBLinter version changed. So I use the following values to re-check files.

• IBLinter version https://github.com/IBDecodable/IBLinter/pull/124/files#diff-c687cb12e1ee55a2364f871dd9c8caa5R33
• .iblinter.yml file hash https://github.com/IBDecodable/IBLinter/pull/124/files#diff-c687cb12e1ee55a2364f871dd9c8caa5R83
• modification date https://github.com/IBDecodable/IBLinter/pull/124/files#diff-c687cb12e1ee55a2364f871dd9c8caa5R65

If the top two are changed, IBLinter ignore existing cache files and re-check all files again.

[kateinoigakukun]

@phimage Thank you for reviewing 🦄