Update build rules and patches for darwin_arm64 platform.

Changes include:

Update nelhage/rules_boost package from current version (08/5/2020) to 5/27/2021 version.
Remove rules_boost-undefine-boost_fallthrough.patch, since BOOST_FALLTHROUGH seems to be defined now.
Minor changes to rules_boost-windows-linkopts.patch to use default condition to add -lpthread flag for all platforms.
Add darwin_arm64 config to BUILD files for lib civetweb pulled in via prometheu dependency.

bazel/ray_deps_setup.bzl

@@ -161,10 +161,9 @@ def ray_deps_setup():
     auto_http_archive(
         name = "com_github_nelhage_rules_boost",
         # If you update the Boost version, remember to update the 'boost' rule.
-        url = "https://github.com/nelhage/rules_boost/archive/2613d04ab3d22dfc4543ea0a083d9adeaa0daf09.tar.gz",
-        sha256 = "512f913240e026099d4ca4a98b1ce8048c99de77fdc8e8584e9e2539ee119ca2",
+        url = "https://github.com/nelhage/rules_boost/archive/652b21e35e4eeed5579e696da0facbe8dba52b1f.tar.gz",
+        sha256 = "c1b8b2adc3b4201683cf94dda7eef3fc0f4f4c0ea5caa3ed3feffe07e1fb5b15",
         patches = [
-            "//thirdparty/patches:rules_boost-undefine-boost_fallthrough.patch",
             "//thirdparty/patches:rules_boost-windows-linkopts.patch",
         ],
     )

thirdparty/patches/prometheus-windows-pollfd.patch

@@ -6,17 +6,46 @@ Windows Vista and later SDKs define struct pollfd for WSAPoll(), but it has a pe
 civetweb provides its own implementation of poll, but it has a conflicting definition for pollfd.
 Hence we block Windows from defining pollfd (which this project doesn't use).
 ---
- bazel/civetweb.BUILD | 1 +
- 1 file changed, 1 insertion(+)
+ bazel/civetweb.BUILD | 7 +++++++
+ 1 file changed, 7 insertions(+)
 
 diff --git bazel/civetweb.BUILD bazel/civetweb.BUILD
 --- bazel/civetweb.BUILD
 +++ bazel/civetweb.BUILD
-@@ -34,5 +34,6 @@ cc_library(
+@@ -9,6 +9,11 @@ config_setting(
+     values = {"cpu": "darwin_x86_64"},
+ )
+
++config_setting(
++    name = "darwin_arm64",
++    values = {"cpu": "darwin_arm64"},
++)
++
+ config_setting(
+     name = "windows",
+     values = { "cpu": "x64_windows" },
+@@ -34,6 +39,7 @@ cc_library(
          "-DNO_CACHING",
          "-DNO_SSL",
          "-DNO_FILES",
 +        "-D_WIN32_WINNT=0x0502",
          "-UDEBUG",
      ],
--- 
+     includes = [
+@@ -46,6 +52,7 @@ cc_library(
+     }) + select({
+         ":darwin": [],
+         ":darwin_x86_64": [],
++        ":darwin_arm64": [],
+         ":windows": [],
+         ":windows_msvc": [],
+         "//conditions:default": ["-lrt"],
+@@ -86,6 +93,7 @@ cc_library(
+     }) + select({
+         ":darwin": [],
+         ":darwin_x86_64": [],
++        ":darwin_arm64": [],
+         ":windows": [],
+         ":windows_msvc": [],
+         "//conditions:default": ["-lrt"],
+--

thirdparty/patches/rules_boost-windows-linkopts.patch

@@ -1,15 +1,12 @@
 diff --git BUILD.boost BUILD.boost
 --- BUILD.boost
 +++ BUILD.boost
-@@ -313,1 +313,9 @@ boost_library(name = "asio",
--    linkopts = ["-lpthread"],
-+    linkopts = select({
-+        ":linux": [
-+            "-lpthread",
-+        ],
-+        ":osx_x86_64": [
-+            "-lpthread",
-+        ],
-+        "//conditions:default": [],
-+    }),
--- 
+@@ -428,6 +428,7 @@ boost_library(
+     }),
+     linkopts = select({
+         ":android": [],
++        ":windows": [],
+         "//conditions:default": ["-lpthread"],
+     }),
+     deps = [
+--