chore: sort imports in the Markdown examples (#3822)

Author: jbampton

docs/en/latest/examples/plugins-hmac-auth-generate-signature.md

@@ -24,9 +24,9 @@ title: HMAC Generate Signature Examples
 ## Python 3
 
 ```python
+import base64
 import hashlib
 import hmac
-import base64
 
 secret = bytes('the shared secret key here', 'utf-8')
 message = bytes('this is signature string', 'utf-8')
@@ -46,8 +46,8 @@ base64.b64encode(hash.digest())
 ```java
 import javax.crypto.Mac;
 import javax.crypto.spec.SecretKeySpec;
-import java.security.NoSuchAlgorithmException;
 import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
 import javax.xml.bind.DatatypeConverter;
 
 class Main {
@@ -103,8 +103,8 @@ func main() {
 ## Ruby
 
 ```ruby
-require 'openssl'
 require 'base64'
+require 'openssl'
 
 secret = 'the shared secret key here'
 message = 'this is signature string'

docs/en/latest/plugins/hmac-auth.md

@@ -168,9 +168,9 @@ Note: The last request header also needs + `\n`.
 Use Python to generate the signature `SIGNATURE`:
 
 ```python
+import base64
 import hashlib
 import hmac
-import base64
 
 secret = bytes('my-secret-key', 'utf-8')
 message = bytes("""GET

docs/zh/latest/plugins/hmac-auth.md

@@ -162,9 +162,9 @@ x-custom-a:test
 使用 Python 来生成签名 `SIGNATURE`：
 
 ```python
+import base64
 import hashlib
 import hmac
-import base64
 
 secret = bytes('my-secret-key', 'utf-8')
 message = bytes("""GET