Bump version to 0.9.0

[ntduyet]

Issue number of the reported bug or feature request: #94

Describe your changes

• Updated the version in the Makefile and ran make update_version per Release.md

Testing performed

• Check the version is updated via running swift run xcdiff --version
• Verify CI passes

[codecov]

Codecov Report

Merging #106 (da42644) into main (bcb6c64) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #106   +/-   ##
=======================================
  Coverage   96.54%   96.54%           
=======================================
  Files          49       49           
  Lines        2636     2636           
=======================================
  Hits         2545     2545           
  Misses         91       91           

Impacted Files	Coverage Δ
Sources/XCDiffCommand/Constants.swift	95.23% <100.00%> (ø)

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[kwridan]

🎉