From Go 1.15

This fixes PEM key decoding issues, and federation

Merge pull request #593 from writefreely/dependabot/go_modules/github.com/microcosm-cc/bluemonday-1.0.21

Bump github.com/microcosm-cc/bluemonday from 1.0.5 to 1.0.21

A Bunch Tell is now Musing Studio.

Bumps [github.com/microcosm-cc/bluemonday](https://github.com/microcosm-cc/bluemonday) from 1.0.5 to 1.0.21.
- [Release notes](https://github.com/microcosm-cc/bluemonday/releases)
- [Commits](https://github.com/microcosm-cc/bluemonday/compare/v1.0.5...v1.0.21

)

---
updated-dependencies:
- dependency-name: github.com/microcosm-cc/bluemonday
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Create container from GitHub action

Update GH-actions

This fixes "unknown revision v1.66.4" error

This fixes build issues we're having due to the SSL certificate
on git.mills.io. It also updates to the latest version of the
go-gopher library.

#514 - Fix login with Gitea OAuth: external user ID not recorded

Fix monetization_pointer upsert query for SQLite

Closes #522

Fixes #495

Fix date format in anonymous posts

Miscellaneous fixes

Elide Markdown when generating slug

This makes sure e.g. link URLs and image alt text don't get included
in the slug.

Ref T329

Templates: use relative URLs for static assets

This fixes an issue where mixing strong and em text caused the text
to not render correctly as a post (e.g. *This is **bold text**.*
would fail).

Fix Gopher collections query

This title, typed directly in the plain editor, would previously crash
the app / show the user a "server error":

# #

fix Dockerfile, nodejs-npm was renamed in alpine to npm