Fix QUICHE standalone build

Also roll enough dependencies forward so that new absl::WriterMutexLock
constructor works.

PiperOrigin-RevId: 805376058
diff --git a/.bazelversion b/.bazelversion
index 66ce77b..a2f28f4 100644
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-7.0.0
+8.4.0
diff --git a/MODULE.bazel b/MODULE.bazel
index 65ba315..f535b6d 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -4,14 +4,14 @@
 
 module(name = "quiche")
 
-# Last updated 2025-02-25
-bazel_dep(name = "bazel_skylib", version = "1.7.1")
+# Last updated 2025-09-09
+bazel_dep(name = "bazel_skylib", version = "1.8.1")
 
-# Last updated 2025-02-25
-bazel_dep(name = "rules_cc", version = "0.1.1")
+# Last updated 2025-09-09
+bazel_dep(name = "rules_cc", version = "0.2.4")
 
-# Last updated 2025-05-29
-bazel_dep(name = "abseil-cpp", version = "20250512.0", repo_name = "com_google_absl")
+# Last updated 2025-09-09
+bazel_dep(name = "abseil-cpp", version = "20250814.0", repo_name = "com_google_absl")
 
 # Last updated 2025-05-29
 bazel_dep(name = "protobuf", version = "31.1", repo_name = "com_google_protobuf")
@@ -28,8 +28,9 @@
 # Last updated 2025-02-25
 bazel_dep(name = "zlib", version = "1.3.1.bcr.5")
 
-# Last updated 2025-06-06
-bazel_dep(name = "fuzztest", version = "20250214.0")
+# Last updated 2025-09-09
+bazel_dep(name = "fuzztest", version = "20250805.0")
+
 # Prevent fuzztest from pulling in a version of riegeli with compilation errors
 # (riegeli version "0.0.0-20240606-973b6f0").
 bazel_dep(name = "riegeli", version = "0.0.0-20241218-3385e3c")
diff --git a/quiche/BUILD.bazel b/quiche/BUILD.bazel
index 718fcda..3a500bd 100644
--- a/quiche/BUILD.bazel
+++ b/quiche/BUILD.bazel
@@ -220,6 +220,7 @@
         "@boringssl//:crypto",
         "@boringssl//:ssl",
         "@com_google_absl//absl/base:core_headers",
+        "@com_google_absl//absl/base:nullability",
         "@com_google_absl//absl/container:flat_hash_map",
         "@com_google_absl//absl/container:flat_hash_set",
         "@com_google_absl//absl/flags:flag",