change: use apisix.enable_http2 to enable HTTP/2 in APISIX

[zll600]

Description

This PR is a Breaking Change.

in #10887, I upgrade openresty-1.25.3.1 for APISIX. There is a deprecation in nginx. The http2 parameter in listen directive is deprecated.

The parameter is deprecated, the http2 directive should be used instead.

In #10887, in order to maintain backward compatibility, I did not modify the method of enable http2 in APISIX. But this will bring a breaking change to users.

for example.
config.yaml

apisix:
  node_listen:
    - ip: 127.0.0.1
      port: 9081
      enable_http2: true  # enable HTTP/2 for 127.0.0.1:9081
    - ip: 127.0.0.2
      port: 9082
      enable_http2: false # disable HTTP/2 for 127.0.0.1:9082

generated nginx.conf which 127.0.0.1:9081 and 127.0.0.2:9082 both can establish HTTP/2 connection. This scenario is not what user want.

    server {
        http2 on;
        listen 127.0.0.1:9081 default_server reuseport;
        listen 127.0.0.2:9082 default_server reuseport;

So I want to make a breaking change for APISIX. Only support apisix.enable_http2. eg.

apisix:
  node_listen:
    - ip: 127.0.0.1
      port: 9081
    - ip: 127.0.0.2
      port: 9082
enable_http2: true # the new way to enable HTTP/2

it will generate following nginx.conf which 127.0.0.1:9081 and 127.0.0.2:9082 both can establish HTTP/2 connection.

    server {
        http2 on;
        listen 127.0.0.1:9081 default_server reuseport;
        listen 127.0.0.2:9082 default_server reuseport;

The original method will no longer be supported. If you still use original way in config.yaml, APISIX will report an error to you.

Checklist

• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible (If not, please discuss on the APISIX mailing list first)

[moonming]

please add break changes in https://github.com/apache/apisix/blob/master/CHANGELOG.md, you can add a new section next release version

[zll600]

please add break changes in https://github.com/apache/apisix/blob/master/CHANGELOG.md, you can add a new section next release version

resolved by 96fd588. PTAL