docs: add info about release schedule (#8546)

docs/contributing/release_schedule.md

@@ -0,0 +1,33 @@
+## Release Schedule
+
+A new minor release for the `deno` cli is released every 6 weeks. A new patch
+version is released weekly, except in the week before a new minor release.
+
+The release dates for the upcoming minor releases are:
+
+- 1.6.0: December 8th, 2020
+- 1.7.0: January 19th, 2020
+- 1.8.0: March 2nd, 2020
+
+Stable releases can be found on the
+[GitHub releases page](https://github.com/denoland/deno/releases).
+
+### Canary channel
+
+In addition to the stable channel described above, canaries are released
+multiple times daily (for each commit on master). You can upgrade to the latest
+canary release by running:
+
+```
+deno upgrade --canary
+```
+
+To update to a specifc canary, pass the commit has in the `--version` option:
+
+```
+deno upgrade --canary --version=973af61d8bb03c1709f61e456581d58386ed4952
+```
+
+To switch back to the stable channel, run `deno upgrade`.
+
+Canaries can be downloaded from https://dl.deno.land.

docs/toc.json

@@ -81,6 +81,7 @@
     "name": "Contributing",
     "children": {
       "building_from_source": "Building from source",
+      "release_schedule": "Release schedule",
       "development_tools": "Development tools",
       "style_guide": "Style guide",
       "architecture": "Architecture"