bazel: remove deprecated python_version

Author: Mizux

ortools/algorithms/python/BUILD.bazel

@@ -72,7 +72,6 @@ pybind_extension(
 py_test(
     name = "knapsack_solver_test",
     srcs = ["knapsack_solver_test.py"],
-    python_version = "PY3",
     deps = [
         ":knapsack_solver",
         requirement("absl-py"),

ortools/init/python/BUILD.bazel

@@ -37,7 +37,6 @@ pybind_extension(
 py_test(
     name = "init_test",
     srcs = ["init_test.py"],
-    python_version = "PY3",
     deps = [
         ":init",
         requirement("absl-py"),

ortools/scheduling/python/BUILD.bazel

@@ -35,7 +35,6 @@ py_test(
     data = [
         "//ortools/scheduling/testdata:j301_1.sm",
     ],
-    python_version = "PY3",
     deps = [
         ":rcpsp",
         "//ortools/scheduling:rcpsp_py_proto",

ortools/set_cover/python/BUILD.bazel

@@ -35,7 +35,6 @@ pybind_extension(
 py_test(
     name = "set_cover_test",
     srcs = ["set_cover_test.py"],
-    python_version = "PY3",
     deps = [
         ":set_cover",
         "//ortools/set_cover:set_cover_py_pb2",

ortools/util/python/BUILD.bazel

@@ -39,7 +39,6 @@ pybind_extension(
 py_test(
     name = "sorted_interval_list_test",
     srcs = ["sorted_interval_list_test.py"],
-    python_version = "PY3",
     deps = [
         ":sorted_interval_list",
         requirement("absl-py"),