colab TF version fix for SoL notebook, images

diffphys-code-sol.ipynb

@@ -158,7 +158,7 @@
     "id": "RY1F4kdWPLNG"
    },
    "source": [
-    "Also let's get installing / importing all the necessary libraries out of the way. And while we're at it, we set the random seed - obviously, 42 is the ultimate choice here \ud83d\ude42"
+    "Also let's get installing / importing all the necessary libraries out of the way. The cell below by default contains a fix for the current colab version. If you're happy with your local install, make sure to disable the TensorFlow version change. And while we're at it, we also set the random seed - obviously, 42 is the ultimate choice here \ud83d\ude42"
    ]
   },
   {
@@ -173,6 +173,8 @@
    },
    "outputs": [],
    "source": [
+    "!yes|pip uninstall tensorflow\n",
+    "!pip install --upgrade --quiet tensorflow==2.9 # for colab ignore msgs, should work despite these\n",
     "!pip install --upgrade --quiet phiflow==2.2\n",
     "from phi.tf.flow import *\n",
     "import tensorflow as tf\n",