docs: store the latest version / latest LTS version in a separate file of APISIX so we can use it to get the latest version in the doc

[spacewander]

Current State

We currently hardcore the APISIX version in the blog or doc, which has misled some newcomers when they read an old blog version. This also makes updating the latest APISIX version in the doc harder, because we need to change several places.

Desired State

Let's add a static file containing the version numbers, and provide a simple one-liner command to get the version number in the doc. The one-liner should be very simple so that we can copy & paste it everywhere.

[juzhiyuan]

cc @navendu-pottekkat

[pottekkat]

We could maybe make a shell script which installs APISIX. It could have flags that user can set to install LTS version or edge releases. Then the one liner will be to pull the .sh file and execute it. All installation logic will be in the script.

[spacewander]

It is a little complex for a good first issue, but I think it is OK.

[biakecw]

I found “docs/*/config.json” and “version.lua” contain version_number 。
As a newcomer, I am a little confused about "in the doc"。It is not clear that the context of the "one-liner" execute

[spacewander]

I mean something in the markdown files.

[juzhiyuan]

Please leave this issue aside 😊 and I will be available 2 ~ 3 weeks later, and then moving forward with the whole document program with @navendu-pottekkat.