fix(commit): attach user info to backup for permission denied issue

[SHAQ522]

For multi user situation, it may get fail

Permission denied: '/tmp/cz.commit.backup'

The reason is another user has already created a temp file with the same name.
So if one user create temp_file should attatch with $USER info to resolve permission issue

Description

attach user info to temp-file name when $USER is possible

Checklist

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

Expected behavior

create /tmp/cz.committom.backup

Steps to Test This Pull Request

Additional context

[codecov]

Codecov Report

Merging #317 (aa2959d) into master (c09f377) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #317   +/-   ##
=======================================
  Coverage   97.17%   97.17%           
=======================================
  Files          35       35           
  Lines         991      991           
=======================================
  Hits          963      963           
  Misses         28       28           

Flag	Coverage Δ
unittests	97.17% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
commitizen/__version__.py	100.00% <100.00%> (ø)
commitizen/commands/commit.py	98.27% <100.00%> (ø)

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[woile]

Awesome, thanks! 🎉