Branch for generated files

Some crates have generated files, and they're not included in the master branch. We have ci_generated branch, that has those generated files.

How it's updated

Done by https://github.com/mozilla-spidermonkey/jsparagus/blob/master/.github/workflows/ci-generated.yml

• Suppose that current master HEAD is A
• commit generated files as X, based on A

... - A <- master
       \
        +- X <- ci_generated

• On the next update, suppose that master head is B
• Merge X and B as MY, discarding all changed from X (so, all generated files are removed in MY)
• commit generated files as Y, based on MY

... - A - ... - B <- master
       \         \
        +- X ---- MY - Y <- ci_generated

• Do the same thing for every update.

... - A - ... - B - ... - C - ... - D <- master
       \         \         \         \
        +- X ---- MY - Y -- MZ - Z -- MW - W <- ci_generated