Fix old link in Installation guide
Fix old link in Installation guide

The TOSCA parser manual installation section refers to an old link
[1] for the TOSCA-Parser source code repository.
The new link for the TOSCA-Parser repository is [2].

[1] https://github.com/openstack/tosca-parser
[2] https://opendev.org/openstack/tosca-parser

Closes-Bug: #1934569
Change-Id: Ie7701e2a74671a0f9a8adda87ffab141e0504e60

openstack/tosca-parser,openstack/tosca-parser