fix(poetry): don't take `python` as a pypi deps (#6490)

lib/manager/poetry/__snapshots__/extract.spec.ts.snap

@@ -473,16 +473,6 @@ Array [
     },
     "versioning": "poetry",
   },
-  Object {
-    "currentValue": "~2.7 || ^3.4",
-    "datasource": "pypi",
-    "depName": "python",
-    "depType": "dependencies",
-    "managerData": Object {
-      "nestedVersion": false,
-    },
-    "versioning": "poetry",
-  },
   Object {
     "currentValue": "^3.0",
     "datasource": "pypi",

lib/manager/poetry/extract.spec.ts

@@ -61,7 +61,7 @@ describe('lib/manager/poetry/extract', () => {
     it('extracts multiple dependencies', () => {
       const res = extractPackageFile(pyproject1toml, filename);
       expect(res.deps).toMatchSnapshot();
-      expect(res.deps).toHaveLength(10);
+      expect(res.deps).toHaveLength(9);
       expect(res.compatibility).toEqual({
         poetry: 'poetry>=1.0 wheel',
         python: '~2.7 || ^3.4',

lib/manager/poetry/extract.ts

@@ -18,6 +18,9 @@ function extractFromSection(
     return [];
   }
   Object.keys(sectionContent).forEach((depName) => {
+    if (depName === 'python') {
+      return;
+    }
     let skipReason: SkipReason;
     let currentValue = sectionContent[depName];
     let nestedVersion = false;