Bump version number to v0.7

[wxh06]

• Change before/after_* to before/after_*ing, iofn to iofile
• Callback function support

[codecov]

Codecov Report

Merging #12 into master will increase coverage by 0.46%.
The diff coverage is 94.11%.

@@            Coverage Diff             @@
##           master      #12      +/-   ##
==========================================
+ Coverage   97.11%   97.58%   +0.46%     
==========================================
  Files           2        2              
  Lines         104      124      +20     
==========================================
+ Hits          101      121      +20     
  Misses          3        3

Impacted Files	Coverage Δ
tests.py	100% <100%> (ø)	⬆️
dockerjudge/__init__.py	95.83% <88.88%> (+0.44%)	⬆️

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