Update Oracle Database 23ai Free version number (#518)

Oracle Database 23ai Free 23.5.0 has been released, so update the
Vagrant project to reflect the new version number:

- Rename the project directory from 23.4.0-Free to 23.5.0-Free
- Update the version number in .env and README.md files

No code changes--the download URL and rpm filename remain the same.

Closes #517

Signed-off-by: Paul Neumann <[email protected]>

Author: PaulNeumann

OracleDatabase/23.4.0-Free/.env renamed to OracleDatabase/23.5.0-Free/.env

@@ -1,4 +1,4 @@
-# Oracle Database 23.4.0 Free configuration file
+# Oracle Database 23.5.0 Free configuration file
 #
 # Requires vagrant-env plugin
 #

OracleDatabase/23.4.0-Free/.gitattributes renamed to OracleDatabase/23.5.0-Free/.gitattributes

@@ -11,7 +11,7 @@ makes configuration much easier
 ## Getting started
 
 1. Clone this repository `git clone https://github.com/oracle/vagrant-projects`
-2. Change into the `vagrant-projects/OracleDatabase/23.4.0-Free` directory
+2. Change into the `vagrant-projects/OracleDatabase/23.5.0-Free` directory
 3. Run `vagrant up`
    1. The first time you run this it will provision everything and may take a while. Ensure you have a good internet connection as the scripts will update the VM to the latest via `dnf`.
    2. The installation can be customized, if desired (see [Configuration](#configuration)).