robot_model: 1.10.20-0 in 'hydro/distribution.yaml' [bloom]

Increasing version of package(s) in repository `robot_model` to `1.10.20-0`:

- upstream repository: https://github.com/ros/robot_model.git
- release repository: https://github.com/ros-gbp/robot_model-release.git
- distro file: `hydro/distribution.yaml`
- bloom version: `0.5.11`
- previous version for package: `1.10.18-1`

## collada_parser

```
* Added extract actuators, fix for using nominal torque
* Removed visual and collision meshes if there are no vertices
* Removed use of visual and collision groups
* Fix problem with root coordinates
* Contributors: YoheiKakiuchi
```

## collada_urdf

```
* Fix clash with assimp 3.1 in CMake.
* Now stores original mesh file name and location
* Contributors: Benjamin Chrétien, YoheiKakiuchi
```

## joint_state_publisher

```
* Update package.xml
  Updating author and maintainer for consistency.
* Contributors: David Lu!!
```

## kdl_parser

```
* add version dependency on orocos_kdl >= 1.3.0
* kdl_parser: Adding kdl library explicitly so that dependees can find it
* Update KDL SegmentMap interface to optionally use shared pointers
  The KDL Tree API optionally uses shared pointers on platforms where
  the STL containers don't support incomplete types.
* Contributors: Brian Jensen, Jonathan Bohren, William Woodall
```

## resource_retriever

- No changes

## robot_model

- No changes

## urdf

- No changes

## urdf_parser_plugin

- No changes