Don't create .gitignore in pkg directory

[mrothNET]

Closes #728 Closes #984, Closes #909 Closes #999. Supersedes #1131, #985

Problematic Behaviour

Currently, wasm-pack generates a .gitignore file in the pkg directory during each build.

Suggested Solution

This PR proposes removing the automatic creation of the .gitignore file without introducing a replacement.

Justification

While many tools generate an appropriate .gitignore during project initialization, it’s relatively uncommon (in my experience) for build tools, like compilers, to create .gitignore files during a build.

Moreover, this behavior has led to several issues, as outlined in the following requests:

• #728
• #984
• #909
• #999

This PR aims to remove the generation of the problematic .gitignore file, addressing and potentially superseding these other PRs:

• #1131
• #985

Changes made

• Remove one line from src/command/utils.rs
• Update documentation in docs/src/commands/build.md

[satindra-r]

was looking for this, hope it gets merged soon

[BadMachine]

any progress?

[jefshe]

bumping! it seems very strange that this is on by default as it's very easy for a dev to add it themselves and causes issues when we want to version control the autogenerated type files

[Enduriel]

Would be really nice to see get added, with --no-pack being a thing it's rather annoying to have a custom package.json to then have it get gitignored because of running a wasm-pack build.