fix: Basic auth plugin should run in rewrite phase. (#2905)

apisix/plugins/basic-auth.lua

@@ -125,7 +125,7 @@ do
     end
 end
 
-function _M.access(conf, ctx)
+function _M.rewrite(conf, ctx)
     core.log.info("plugin access phase, conf: ", core.json.delay_encode(conf))
 
     -- 1. extract authorization from header

t/plugin/basic-auth.t

@@ -198,6 +198,8 @@ Authorization: Basic Zm9vOmJhcg==
 hello world
 --- no_error_log
 [error]
+--- error_log
+find consumer foo