Bump JGit submodule to the tip of stable-7.5

Re-pin modules/jgit from the stable-7.4 branch to the tip of stable-7.5.

stable-7.5 is the newer JGit stable line and has not been migrated to
bzlmod, so it is still consumable by this WORKSPACE-based stable-3.12
branch, which builds JGit from source via EE8 servlet bridge.

Release-Notes: Bump JGit submodule to the tip of stable-7.5 branch
Change-Id: Ib2390b1e8e59acc7cc59d47fb35f78fdec19bd5e

modules/jgit

diff --git a/modules/jgit b/modules/jgit
index c2188c2..94fe3e8 160000
--- a/modules/jgit
+++ b/modules/jgit
@@ -1 +1 @@
-Subproject commit c2188c2a078df7b4112ef7d95dc8f0e4d76083f2
+Subproject commit 94fe3e89f0e869643fba0e2a47cb3c6b7ea7b4d3