Update guides to show support for Ruby 2.7 and 3.0

The ManageIQ project has recently added Ruby 3.0 support and dropped
Ruby 2.6 support.

developer_setup.md

@@ -4,7 +4,7 @@
 
 | **Name**   | **Min Version** | **Max Version** |
 | ---------- | --------------- | --------------- |
-| Ruby       | 2.6.x           | 2.7.x           |
+| Ruby       | 2.7.x           | 3.0.x           |
 | Bundler    | 2.1.4           | 2.x             |
 | NodeJS     | 14.x.x          |                 |
 | Python     | 3.8.x           |                 |
@@ -148,13 +148,13 @@ A Ruby version manager is *strongly* recommended. Use any one of the following:
 * [rbenv](https://github.com/rbenv/rbenv) + [ruby-build](https://github.com/rbenv/ruby-build#readme)
 * [rvm](http://rvm.io/)
 
-Using the Ruby version manager, install `ruby` >= 2.6.0 and < 3.0.0 and the latest `bundler`.
+Using the Ruby version manager, install `ruby` >= 2.7.0 and < 3.1.0 and the latest `bundler`.
 
 ---
 
 ## Clone ManageIQ
 
-You must first fork the repository, clone it and then create an upstream remote. Additionally, to run the following commands you will need to setup an SSH key. Detailed instructions on how to do (as well as set up the recommended git and GitHub options) can be found in [Git workflow](developer_setup/git_workflow.md). 
+You must first fork the repository, clone it and then create an upstream remote. Additionally, to run the following commands you will need to setup an SSH key. Detailed instructions on how to do (as well as set up the recommended git and GitHub options) can be found in [Git workflow](developer_setup/git_workflow.md).
 
 ```bash
 git clone [email protected]:<username>/manageiq.git

vagrant_developer_vm.md

@@ -76,7 +76,7 @@ The Vagrant file will create a VM using Fedora 33 as a basis and proceed to conf
 - Install python (needed by Ansible) so the Ansible playbook.yml can be run
 - Configure the OS and install everything needed for development
 - Configure the database, start and enable it and add the user needed
-- Configure rbenv and install ruby 2.6.5
+- Configure rbenv and install ruby 3.0.x
 - Verify if reboot is necessary and then reboot the machine