Expand and update release instructions

Author: horgh

README.dev.md

@@ -3,16 +3,20 @@
 * Update changelog: Set version and release date
 * Set version in `maxmind-db.gemspec`
 * Add them: `git add -p`
+* Create a branch e.g. `horgh/release` and switch to it.
+  * `main` is protected.
 * Commit: `git commit -m v1.0.0`
 * Tag: `git tag -a v1.0.0 -m v1.0.0`
 * Clean up to be sure nothing stray gets into gem: `git clean -dxff`
 * Create `.gem` file: `gem build maxmind-db.gemspec`
 * Complete prerequisites (see below)
-  * You only need to do this if `~/.gem/credentials` is missing
-    `:rubygems_api_key`.
+  * You only need to do this once. You can tell if this is necessary if you
+    are lacking `:rubygems_api_key` in `~/.local/share/gem/credentials`
+    (previously `~/.gem/credentials`)
 * Upload to rubygems.org: `gem push maxmind-db-1.0.0.gem`
 * Push: `git push`
 * Push tag: `git push --tags`
+* Make a PR and get it merged.
 * Double check it looks okay at https://rubygems.org/gems/maxmind-db and
   https://www.rubydoc.info/gems/maxmind-db
 
@@ -22,7 +26,7 @@
 ## Step 1
 Sign up for an account at rubygems.org if you don't have one.
 
-Enable multi factor authentication.
+Enable multi factor authentication (for both UI and API).
 
 
 ## Step 2
@@ -33,5 +37,9 @@ They do this by using the `gem owner` command
 
 
 ## Step 3
-Go to your rubygems.org profile and find the curl command to run to
-download your API key.
+Run `gem signin`. This will prompt you for your username and password, and
+then create an API key for you. Select the scopes `index_rubygems` and
+`push_rubygem` (I'm not sure the former is required, but anyway).
+
+Note you may need an up to date version of rubygems to do this as I believe
+support for API keys like this is a newer addition.