Set Update Mechanism to Manual

This CL sets the Update Mechanism to Manual in README files.

Bug: 445311061
Change-Id: I181d1ce74cbb1e4e6f0a5005189ffb9ab99d32f2
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/77108
Reviewed-by: Geoff Lang <geofflang@google.com>
Presubmit-Ready: Geoff Lang <geofflang@google.com>
Commit-Queue: Geoff Lang <geofflang@google.com>
Tested-by: Geoff Lang <geofflang@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@google.com>

third_party/subzero/bloat/README.chromium

diff --git a/third_party/subzero/bloat/README.chromium b/third_party/subzero/bloat/README.chromium
index 8b4ef4d..e2dd108 100644
--- a/third_party/subzero/bloat/README.chromium
+++ b/third_party/subzero/bloat/README.chromium
@@ -6,6 +6,7 @@
 Revision: 2c22b831f081402a9160adb957b64b83316202e1
 License: Apache-2.0
 Security Critical: no
+Update Mechanism: Manual
 Shipped: no
 
 Description:
@@ -24,6 +25,7 @@
 Revision: a2fa353833eca1a4821ba4c93fb6a7d546aed02a
 License: Apache-2.0
 Security Critical: no
+Update Mechanism: Manual
 Shipped: no
 
 Description: