epubcheck: update URLs

Closes #35163.

Signed-off-by: Tim D. Smith <git@tim-smith.us>
libbpg 0.9.4

Closes #35162.

Signed-off-by: Tim D. Smith <git@tim-smith.us>
libbpg: update 0.9.4 bottle.
pandoc 1.13.2

Closes #35160.

Signed-off-by: Tim D. Smith <git@tim-smith.us>
pandoc: update 1.13.2 bottle.
apache-spark 1.2.0

Closes #35158.

Signed-off-by: Tim D. Smith <git@tim-smith.us>
pygobject3: fix python3 external linking

See comment below in the PR for explanation.
pygobject3: add 3.14.0 bottle.