Bug#999415: transition: pandas 1.1 -> 1.3

[Rebecca N. Palmer]

1.3.4 is now in experimental.

Lots of tests failed on non-amd64 (the build "succeeded" because these 
were intentionally ignored), but it looks plausible that they're only a 
few easily-fixable problems.

Reverse dependencies testing is in progress.  (At least some of the 
failures in 
https://release.debian.org/britney/pseudo-excuses-experimental.html#pandas 
look like attempts to import something in Python 3.10 that hasn't been 
built for 3.10 yet, so probably just require waiting for that.)