Pin pybind11_bazel to the same version currently used for pybind11_protobuf.

Leave it for later to resolve the `ubuntu-latest bazel` failure:

* https://github.com/pybind/pybind11_bazel/issues/94

```
ERROR: /home/runner/work/pybind11_abseil/pybind11_abseil/pybind11_abseil/tests/BUILD:92:17: Linking pybind11_abseil/tests/missing_import.so failed: (Exit 1): gcc failed: error executing CppLink command (from target //pybind11_abseil/tests:missing_import.so) /usr/bin/gcc @bazel-out/k8-fastbuild/bin/pybind11_abseil/tests/missing_import.so-2.params

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
/usr/bin/ld.gold: undefs: unknown -z option
```

PiperOrigin-RevId: 659560021

MODULE.bazel

@@ -29,19 +29,9 @@ bazel_dep(
     version = "0.0.8"
 )
 
-http_archive = use_repo_rule("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
-
-http_archive(
-  name = "pybind11_bazel",
-  strip_prefix = "pybind11_bazel-master",
-  urls = ["https://github.com/pybind/pybind11_bazel/archive/refs/heads/master.tar.gz"],
-)
-
-http_archive(
-  name = "pybind11",
-  build_file = "@pybind11_bazel//:pybind11-BUILD.bazel",
-  strip_prefix = "pybind11-master",
-  urls = ["https://github.com/pybind/pybind11/archive/refs/heads/master.tar.gz"],
+bazel_dep(
+    name = "pybind11_bazel",
+    version = "2.11.1.bzl.2",
 )
 
 #### DEV ONLY DEPENDENCIES BELOW HERE ####

WORKSPACE

@@ -90,19 +90,20 @@ load("@pypi//:requirements.bzl", "install_deps")
 install_deps()
 
 
-## `pybind11_bazel` (FLOATING)
+## `pybind11_bazel` (PINNED)
 # https://github.com/pybind/pybind11_bazel
 http_archive(
   name = "pybind11_bazel",
-  strip_prefix = "pybind11_bazel-master",
-  urls = ["https://github.com/pybind/pybind11_bazel/archive/refs/heads/master.tar.gz"],
+  strip_prefix = "pybind11_bazel-2.11.1.bzl.2",
+  sha256 = "e2ba5f81f3bf6a3fc0417448d49389cc7950bebe48c42c33dfeb4dd59859b9a4",
+  urls = ["https://github.com/pybind/pybind11_bazel/releases/download/v2.11.1.bzl.2/pybind11_bazel-2.11.1.bzl.2.tar.gz"],
 )
 
 ## `pybind11` (FLOATING)
 # https://github.com/pybind/pybind11
 http_archive(
   name = "pybind11",
-  build_file = "@pybind11_bazel//:pybind11-BUILD.bazel",
+  build_file = "@pybind11_bazel//:pybind11.BUILD",
   strip_prefix = "pybind11-master",
   urls = ["https://github.com/pybind/pybind11/archive/refs/heads/master.tar.gz"],
   # For easy local testing with pybind11 releases: