[FEATURE] template for OpenSearch 2.x?

[rursprung]

Is your feature request related to a problem?

the current major release of OpenSearch is 2.x, however the template for plugins already targets 3.x and isn't compatible with 2.x anymore.

What solution would you like?

there should be a template for 2.x (or a tag on this repo which can be used as a reference)

What alternatives have you considered?

taking the current template main and try to manually downgrade it to 2.x is error-prone and (unnecessary) effort.

Do you have any additional context?

3.x is probably still a year away (see the release discussion on OpenSearch itself), so the template should primarily target the currently used major release.