chore: adapt README.md from ooni/oohttp

README.md

@@ -0,0 +1,52 @@
+# github.com/ooni/oocrypto
+
+This repository contains a fork of the Go standard library's `crypto`
+package including patches to allow selecting AES hardware support
+on Android devices. We documented why we need these patches at OONI in
+the [Making the OONI Probe Android app more resilient](
+https://ooni.org/post/making-ooni-probe-android-more-resilient/) blog post.
+
+## Motivation and maintenance
+
+To solve our issues with Android apps, we originally forked golang/go
+itself at [ooni/go](https://github.com/ooni/go). However, a full fork of
+Go required us to compile this fork and build Android apps using it,
+which was making building OONI excessively complicated. Hence, we later
+chose to just fork the `crypto` package. We will continue to keep this
+fork up to date as long as it serves our goals.
+
+## License
+
+Each individual file from the `crypto` fork maintains its original
+copyright and any change to such files authored by us keeps the same
+BSD license of the original code. Because we anticipate integrating
+code under the GPL license from `Yawning/utls` we chose to license the
+repository using the GPL.
+
+```
+SPDX-License-Identifier: GPL-3.0-or-later
+```
+
+## Issue tracker
+
+Please, report issues in the [ooni/probe](https://github.com/ooni/probe)
+repository. Make sure you mention `oocrypto` in the issue title.
+
+## Update procedure
+
+(Adapted from ooni/oohttp instructions.)
+
+- [ ] run the following commands:
+
+```bash
+set -ex
+git checkout main
+git remote add golang git@github.com:golang/go.git || git fetch golang
+git branch -D golang-upstream golang-http-upstream merged-main || true
+git fetch golang
+git checkout -b golang-upstream go1.17.10
+git subtree split -P src/crypto/ -b golang-http-upstream
+git checkout main
+git checkout -b merged-main
+git merge golang-http-upstream
+```