refactor: replace deprecated String.prototype.substr() (#281)

.substr() is deprecated so we replace it with .slice() which works similarily but isn't deprecated

Author: CommanderRoot

auth-next/apple.js

@@ -169,7 +169,7 @@ function appleNonceNode() {
       crypto.randomFillSync(buf);
       nonce = decoder.write(buf);
     }
-    return nonce.substr(0, length);
+    return nonce.slice(0, length);
   };
 
   const unhashedNonce = generateNonce(10);

auth/apple.js

@@ -170,7 +170,7 @@ function appleNonceNode() {
       crypto.randomFillSync(buf);
       nonce = decoder.write(buf);
     }
-    return nonce.substr(0, length);
+    return nonce.slice(0, length);
   };
 
   const unhashedNonce = generateNonce(10);

scripts/separate-snippets.ts

@@ -77,7 +77,7 @@ function adjustIndentation(lines: string[]) {
     if (isBlank(line)) {
       outputLines.push("");
     } else {
-      outputLines.push(line.substr(minIndent));
+      outputLines.push(line.slice(minIndent));
     }
   }
   return outputLines;

snippets/auth-next/apple/auth_apple_nonce_node.js

@@ -17,7 +17,7 @@ const generateNonce = (length) => {
     crypto.randomFillSync(buf);
     nonce = decoder.write(buf);
   }
-  return nonce.substr(0, length);
+  return nonce.slice(0, length);
 };
 
 const unhashedNonce = generateNonce(10);