Add fontTools, brotli, pytest to fontbuilder image lockfile

These are needed by the upcoming release-artifact generator
(fontTools for table-level font manipulation, brotli for WOFF2,
pytest for the unit-test suite that runs in CI).

Existing transitive pins are held by passing requirements.txt as a
self-constraint, so no other versions move.

Author: pelson

xkcd-script/generator/requirements.in

@@ -2,3 +2,6 @@ scikit-image
 scipy
 matplotlib
 parse
+fonttools
+brotli
+pytest

xkcd-script/generator/requirements.txt

@@ -1,7 +1,9 @@
+brotli==1.2.0
 contourpy==1.3.3
 cycler==0.12.1
 fonttools==4.62.1
 imageio==2.37.3
+iniconfig==2.3.0
 kiwisolver==1.5.0
 lazy-loader==0.5
 matplotlib==3.10.9
@@ -10,7 +12,10 @@ numpy==2.4.4
 packaging==26.2
 parse==1.22.0
 pillow==12.2.0
+pluggy==1.6.0
+pygments==2.20.0
 pyparsing==3.3.2
+pytest==9.1.0
 python-dateutil==2.9.0.post0
 scikit-image==0.26.0
 scipy==1.17.1