Update URLs for pdf and reference

[ronaldtse]

From Janet Miles of BIPM:

In the YAML files:

I see that two different URLs are given for the “pdf” and “reference” (which correspond to the document on the BIPM website).
Can you please omit the segment “?version=1.3&download=true”, and for the links use the versions as given on https://www.bipm.org/en/committees/cg/cgpm/publications, https://www.bipm.org/en/committees/ci/cipm/publications, https://www.bipm.org/en/committees/ci/cipm/older-meeting-reports, https://www.bipm.org/en/committees/cc/cctf/publications
(Unfortunately the documents are posted twice.)