chore: add .git to .dockerignore

[afreakk]

Add .git to .dockerignore, a lot more could probably be added to .dockerignore, but atleast .git should not be copied over.
Before added .git to .dockerignore:

at 17:39:06 ❯ docker build .
Sending build context to Docker daemon  949.8kB
Step 1/14 : FROM node:17.0-alpine
 ---> c0fc1c9c473b
...snipped...
Successfully built 92f2ee319e75

at 17:39:22 ❯ docker run -it --entrypoint /bin/sh  92f2ee319e75
/usr/src/app $ ls .git
.git

After:

at 17:42:39 ❯ docker build .
Sending build context to Docker daemon  948.7kB
Step 1/14 : FROM node:17.0-alpine
 ---> c0fc1c9c473b
...snipped...
Successfully built 5cb0247274a4

at 17:42:48 ❯ docker run -it --entrypoint /bin/sh  5cb0247274a4
/usr/src/app $ ls .git
ls: .git: No such file or directory

Related Issue or Design Document

Checklist

• I have read the contributing guidelines and signed the CLA.
• I have referenced an issue containing the design document if my change introduces a new feature.
• I have read the security policy.
• I confirm that this pull request does not address a security vulnerability.
  If this pull request addresses a security vulnerability,
  I confirm that I got approval (please contact [email protected]) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works.
• I have added the necessary documentation within the code base (if appropriate).

Further comments

[zepatrik]

Sorry, this got a bit lost.