Fix kernel display name in the metadata.

CI fails if the kernel name doesn't exist as an environment on the runner.

Author: p-j-smith

ch00python/010exemplar.ipynb

@@ -1156,9 +1156,9 @@
    "display_name": "An example program"
   },
   "kernelspec": {
-   "display_name": "Python [conda env:rsd-course]",
+   "display_name": "Python 3",
    "language": "python",
-   "name": "conda-env-rsd-course-py"
+   "name": "python3"
   },
   "language_info": {
    "codemirror_mode": {
@@ -1170,7 +1170,12 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.13"
+   "version": "3.9.6"
+  },
+  "vscode": {
+   "interpreter": {
+    "hash": "31f2aee4e71d21fbe5cf8b01ff0e069b9275f58929596ceb00d14d90e3e16cd6"
+   }
   }
  },
  "nbformat": 4,