update README.md

A sphinx-based documentation is available at

- [https://csst-proto.readthedocs.io/en/latest/](https://csst-proto.readthedocs.io/en/latest/)

## dependency

- numpy~=1.20.3

- joblib~=1.1.0

- astropy~=5.1

## installation

`csst_common` can be installed with the following shell command

```bash

git clone https://csst-tb.bao.ac.cn/code/csst-l1/csst_common.git

cd csst_common

pip install -r requirements.txt

python setup.py install

pip install git+https://csst-tb.bao.ac.cn/code/csst-l1/csst_common.git

```

or a single-line command

## dependency

- numpy

- astropy

- pyyaml

- setuptools>65.0.0

```bash

sh -c "$(curl -fsSL https://csst-tb.bao.ac.cn/code/csst-l1/csst_common/-/raw/main/install.sh)"

```

install CCDS: 

## instruction

    pip install git+https://csst-tb.bao.ac.cn/code/csst-dfs/ccds.git

install DFS:

    sh -c "$(curl -fsSL https://csst-tb.bao.ac.cn/code/csst-dfs/csst-dfs-api/-/raw/master/tools/csst-dfs-api-install.sh)"

how to import CSST parameters:

```python

from csst_common.params import CSST_PARAMS as CP

print(CP)

print(CP["mbi"]["detector2filter"])

```