[#171] Updating gitignore to account for bin folder

[Eclipse-Dominator]

Fixes #171

Previously, running the command ./gradlew generated a bin folder containing all the .class files. To prevent accidentally committing files to the repository, let's adds /bin/ to the .gitignore file

[canihasreview[bot]]

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[codecov-commenter]

Codecov Report

Merging #175 (17dc864) into master (1e05fef) will not change coverage. The diff coverage is n/a.

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@@            Coverage Diff            @@
##             master     #175   +/-   ##
=========================================
  Coverage     72.15%   72.15%           
  Complexity      399      399           
=========================================
  Files            70       70           
  Lines          1232     1232           
  Branches        125      125           
=========================================
  Hits            889      889           
  Misses          311      311           
  Partials         32       32           

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[canihasreview[bot]]

v1

@Eclipse-Dominator submitted v1 for review.

• [v1 1/1] Add bin/ folder to .gitignore

(:books: Archive)

Checkout this PR version locally

```sh git fetch https://github.com/se-edu/addressbook-level3.git refs/pr/175/1/head:BRANCHNAME ``` where `BRANCHNAME` is the name of the local branch you wish to fetch this PR to.

[damithc]

I could not reproduce this behavior on Windows i.e., I ran gradlew but it did not create a bin folder. 🤔

Commit message: generated -> generates?

[Eclipse-Dominator]

After some investigation, the creation of bin/ folder seems to be caused by a separate vscode extension. As the focus of the module is the use of Intellij, let's close this for now.