ci: remove whitelist of whitespace check (apache#4203)

.github/workflows/lint.yml

@@ -9,7 +9,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: 🧹 Check for trailing whitespace
-        run: "! git grep -EIn $'[ \t]+$' | grep -v 'received: '"
+        run: "! git grep -EIn $'[ \t]+$'"
   misc:
     name: misc checker
     runs-on: ubuntu-latest

t/lib/test_admin.lua

@@ -91,7 +91,11 @@ function _M.test_ipv6(uri)
     while true do
         local line, err, part = sock:receive()
         if line then
-            ngx.say("received: ", line)
+            if line ~= "" then
+                ngx.say("received: ", line)
+            else
+                ngx.say("received:")
+            end
 
         else
             ngx.say("failed to receive a line: ", err, " [", part, "]")

t/node/remote-addr-ipv6.t

@@ -108,7 +108,7 @@ received: Content-Type: text/plain
 received: Content-Length: 12
 received: Connection: close
 received: Server: APISIX/\d\.\d+(\.\d+)?
-received: 
+received:
 received: hello world
 failed to receive a line: closed \[\]
 close: 1 nil}