[build] Specify the location of python3 binary

Author: AutomatedTester

BUILD.bazel

@@ -11,6 +11,27 @@ filegroup(
     visibility = ["//visibility:public"],
 )
 
+load("@rules_python//python:defs.bzl", "py_runtime_pair")
+
+py_runtime(
+    name = "py3_runtime",
+    interpreter_path = "/usr/bin/python3",
+    python_version = "PY3",
+    stub_shebang = "#!/usr/bin/python3",
+)
+
+py_runtime_pair(
+    name = "py_runtime_pair",
+    py2_runtime = None,
+    py3_runtime = ":py3_runtime",
+)
+
+toolchain(
+    name = "py_toolchain",
+    toolchain = ":py_runtime_pair",
+    toolchain_type = "@rules_python//python:toolchain_type",
+)
+
 alias(
     name = "grid",
     actual = "//java/src/org/openqa/selenium/grid:executable-grid",

WORKSPACE

@@ -6,6 +6,8 @@ workspace(
     },
 )
 
+register_toolchains(":py_toolchain")
+
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 http_archive(