Roll third_party/zlib/ a68151fd9..8603eee37 (5 commits)

https://chromium.googlesource.com/chromium/src/third_party/zlib.git/+log/a68151fd9b9f..8603eee37c4f

Created with:
  roll-dep third_party/zlib

Tbr: dhoss@chromium.org
Change-Id: I3649dfab50988a162fe4e395dd91b6df9de4de72
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/71017
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/DEPS b/DEPS
index 9085767..a769188 100644
--- a/DEPS
+++ b/DEPS
@@ -99,7 +99,7 @@
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling zlib
   # and whatever else without interference from each other.
-  'zlib_revision': 'a68151fd9b9f5ad11b96a3765f706361ff22dbc8',
+  'zlib_revision': '8603eee37c4f4dd3e033d06fa18ea34ed9b41f41',
 }
 
 deps = {