Update notebooks to latest nbformat

03_classification.ipynb

@@ -1163,9 +1163,7 @@
   },
   {
    "cell_type": "markdown",
-   "metadata": {
-    "collapsed": true
-   },
+   "metadata": {},
    "source": [
     "# Exercise solutions"
    ]
@@ -2553,7 +2551,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.3"
+   "version": "3.7.6"
   },
   "nav_menu": {},
   "toc": {
@@ -2567,5 +2565,5 @@
   }
  },
  "nbformat": 4,
- "nbformat_minor": 1
+ "nbformat_minor": 4
 }