install: update to fix AmazonLinux versions

[patrick-stephens]

Resolves #7352 by ensuring we fix it to 2023 or 2 depending on the AL version.

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Enter [N/A] in the box, if an item is not applicable to your change.

Testing

Verified locally using containers:

$ docker run --rm -it -v $PWD/install.sh:/install.sh:ro amazonlinux:2023
bash-5.2# ./install.sh 
================================
 Fluent Bit Installation Script 
================================
This script requires superuser access to install packages.
You will be prompted for your password by sudo.
[fluent-bit]
name = Fluent Bit
# Legacy server style
baseurl = https://packages.fluentbit.io/amazonlinux/2023
...

$ docker run --rm -it -v $PWD/install.sh:/install.sh:ro amazonlinux:2
bash-4.2# /install.sh 
================================
 Fluent Bit Installation Script 
================================
This script requires superuser access to install packages.
You will be prompted for your password by sudo.
[fluent-bit]
name = Fluent Bit
# Legacy server style
baseurl = https://packages.fluentbit.io/amazonlinux/2
...

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[patrick-stephens]

Github is having an incident hence the failures