Update the release procedure documentation

[costin-zaharia-sonarsource]

https://xtranet-sonarsource.atlassian.net/wiki/spaces/SSG/pages/1181769/Scanner+for+.NET+Release+Process

Changes made: https://xtranet-sonarsource.atlassian.net/wiki/pages/diffpagesbyversion.action?pageId=1181769&selectedPageVersions=80&selectedPageVersions=76

Notes:

• The scanner will update automatically for autoscan but the scanner-cli will not. We need add a note to manually update the scanner cli when it changes in the autoscan. https://github.com/SonarSource/sonar-dotnet-autoscan/blob/master/its/src/test/java/com/sonarsource/autoscan/net/its/Tests.java#L84-L86