refactor(pip): expand matches logic

lib/manager/pip_requirements/extract.js

@@ -20,14 +20,16 @@ function extractDependencies(content) {
     .map((line, lineNumber) => {
       regex.lastIndex = 0;
       const matches = regex.exec(line);
-      return (
-        matches && {
-          depName: matches[1],
-          currentValue: matches[2],
-          lineNumber,
-          versionScheme: 'pep440',
-        }
-      );
+      if (!matches) {
+        return null;
+      }
+      const [, depName, currentValue] = matches;
+      return {
+        depName,
+        currentValue,
+        lineNumber,
+        versionScheme: 'pep440',
+      };
     })
     .filter(Boolean);
   if (!deps.length) {