website updates

Summary:
A few small website updates:

- changed the tutorials to point to the `stable` tag on github so we don't have to update the website each time we want to run them!
- changed the colab button
- re ran notebook cells to update the images for textured meshes

Once these fixes are landed I can build and publish the website.

Reviewed By: bottler

Differential Revision: D20484836

fbshipit-source-id: 603a05e752f631c60d1a3abb9adeb1b9b451ab98

docs/tutorials/bundle_adjustment.ipynb

@@ -83,7 +83,7 @@
    "outputs": [],
    "source": [
     "!pip install torch torchvision\n",
-    "!pip install 'git+https://github.com/facebookresearch/pytorch3d.git'"
+    "!pip install 'git+https://github.com/facebookresearch/pytorch3d.git@stable'"
    ]
   },
   {

docs/tutorials/camera_position_optimization_with_differentiable_rendering.ipynb

@@ -70,7 +70,7 @@
    "outputs": [],
    "source": [
     "!pip install torch torchvision\n",
-    "!pip install 'git+https://github.com/facebookresearch/pytorch3d.git'"
+    "!pip install 'git+https://github.com/facebookresearch/pytorch3d.git@stable'"
    ]
   },
   {

docs/tutorials/deform_source_mesh_to_target_mesh.ipynb

@@ -85,7 +85,7 @@
    "outputs": [],
    "source": [
     "!pip install torch torchvision\n",
-    "!pip install 'git+https://github.com/facebookresearch/pytorch3d.git'"
+    "!pip install 'git+https://github.com/facebookresearch/pytorch3d.git@stable'"
    ]
   },
   {