DOC: Unable to install pre-release
#### Location of the documentation

["https://github.com/pandas-dev/pandas/releases/tag/v1.1.0rc0"]

#### Documentation problem

It seems that I am not able to install the v1.1.0 version of the Pandas package using the following commands: 

```
python -m pip install --upgrade --pre pandas==1.1.0rc0

conda install -c conda-forge/label/rc pandas==1.1.0rc0

```

It says that: 

PackagesNotFoundError: The following packages are not available from current channels:

  - pandas==1.1.0rc0

Current channels:

```
  - https://conda.anaconda.org/conda-forge/label/rc/osx-64
  - https://conda.anaconda.org/conda-forge/label/rc/noarch
  - https://repo.anaconda.com/pkgs/main/osx-64
  - https://repo.anaconda.com/pkgs/main/noarch
  - https://repo.anaconda.com/pkgs/r/osx-64
  - https://repo.anaconda.com/pkgs/r/noarch
```