DOC: Remove 1.2 versionadded and changed

[phofl]

Lets see if the docs build like this

[rhshadrach]

Was curious about recent PyPI downloads - here they are for the last 30 days and 365 days respectively after stripping off the patch version.

# Last 30 days
         num_downloads       pct
version                         
2.1           37113461  0.242764
1.3           27127663  0.177446
2.0           21945922  0.143551
1.5           21767650  0.142385
1.1           12604581  0.082448
1.2           11386654  0.074482
1.0            8958391  0.058598
1.4            5990242  0.039183
0.24           2742404  0.017938
0.25           1985167  0.012985
0.22            506227  0.003311
0.23            466675  0.003053
0.20             94863  0.000621
0.19             80029  0.000523
0.21             50860  0.000333
0.18             30623  0.000200
0.17              6348  0.000042
0.16              4729  0.000031
0.15              3692  0.000024
0.14              1846  0.000012

# Last 365 days
         num_downloads       pct
version                         
1.3          323629530  0.213405
1.5          263981724  0.174073
2.0          213161185  0.140561
1.1          183277328  0.120855
1.2          142029794  0.093656
2.1          110269020  0.072713
1.0           97492902  0.064288
1.4           83294693  0.054926
0.24          42107295  0.027766
0.25          37070776  0.024445
0.23           9389390  0.006191
0.22           5793919  0.003821
0.20           2013760  0.001328
0.19           1245090  0.000821
0.21            721957  0.000476
0.18            374775  0.000247
0.17            172063  0.000113
0.16             81421  0.000054
0.15             61217  0.000040
0.7              55964  0.000037

[phofl]

We can't keep these notes around forever, folks can just use the version switch if they are still back on 1.3. 1.3 was released 2 years ago and this will land in the 5th release since then

[rhshadrach]

lgtm

[rhshadrach]

Thanks @phofl