comment flask click and itsdangerous restrictions

[cbouss]

Following PR #184, older versions of anaconda fail to install:

conda create -n anaconda-2022.05_py39 anaconda==2022.05 python=3.9

LibMambaUnsatisfiableError: Encountered problems while solving:

• package flask-1.1.2-pyhd3eb1b0_0 requires click >=5.1,<8.0, but none of the providers can be installed

It seems we can do away without the added restrictions on click and itsdangerous.