Temporarily restore //mappings.bzl and //pkg.bzl (#817)

* Restore mappings.bzl and pkg.bzl as a stopgap until https://github.com/protocolbuffers/protobuf/issues/15779 is fixed.

* bump version number for upcoming patch release

mappings.bzl

@@ -0,0 +1,41 @@
+# Copyright 2021 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load(
+    "//pkg:mappings.bzl",
+    _filter_directory = "filter_directory",
+    _pkg_attributes = "pkg_attributes",
+    _pkg_filegroup = "pkg_filegroup",
+    _pkg_files = "pkg_files",
+    _pkg_mkdirs = "pkg_mkdirs",
+    _pkg_mklink = "pkg_mklink",
+    _strip_prefix = "strip_prefix",
+    _REMOVE_BASE_DIRECTORY = "REMOVE_BASE_DIRECTORY",
+)
+
+REMOVE_BASE_DIRECTORY = _REMOVE_BASE_DIRECTORY
+
+filter_directory = _filter_directory
+
+pkg_attributes = _pkg_attributes
+
+pkg_filegroup = _pkg_filegroup
+
+pkg_files = _pkg_files
+
+pkg_mkdirs = _pkg_mkdirs
+
+pkg_mklink = _pkg_mklink
+
+strip_prefix = _strip_prefix

pkg.bzl

@@ -0,0 +1,21 @@
+# Copyright 2021 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+load("//pkg:deb.bzl", _pkg_deb = "pkg_deb")
+load("//pkg:tar.bzl", _pkg_tar = "pkg_tar")
+load("//pkg:zip.bzl", _pkg_zip = "pkg_zip")
+
+pkg_deb = _pkg_deb
+pkg_tar = _pkg_tar
+pkg_zip = _pkg_zip

version.bzl

@@ -13,4 +13,4 @@
 # limitations under the License.
 """The version of rules_pkg."""
 
-version = "0.10.0"
+version = "0.10.1"