refactor: 스타일 가이드에 따른 파일 이름 수정

[kite707]

📌Solved Issue

close #20

🔑Key Changes

스타일 가이드에 따라 파일 이름을 변경하였습니다.

[github-actions]

Running main() from /home/runner/work/INHA_OSAP_002_Honeycomb/INHA_OSAP_002_Honeycomb/build/_deps/googletest-src/googletest/src/gtest_main.cc
[==========] Running 3 tests from 3 test suites.
[----------] Global test environment set-up.
[----------] 1 test from AVL
[ RUN ] AVL.avlTree_Test
[ OK ] AVL.avlTree_Test (0 ms)
[----------] 1 test from AVL (0 ms total)

[----------] 1 test from SET
[ RUN ] SET.set_Test
[ OK ] SET.set_Test (0 ms)
[----------] 1 test from SET (0 ms total)

[----------] 1 test from MAIN
[ RUN ] MAIN.mainTest
[ OK ] MAIN.mainTest (0 ms)
[----------] 1 test from MAIN (0 ms total)

[----------] Global test environment tear-down
[==========] 3 tests from 3 test suites ran. (0 ms total)
[ PASSED ] 3 tests.