remove deprecated git-secret.plugin.zsh (#387)

git-secret.plugin.zsh

@@ -1,26 +0,0 @@
-#!/usr/bin/env zsh
-
-# Copyright 2016 Sobolev Nikita <mail@sobolevn.me>
-#
-# Licensed under the MIT License
-
-# 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.
-
-# Deprecation warning:
-(>&2 echo "warning: this installation method is deprecated since version 0.2.3")
-(>&2 echo "warning: it will be completely removed by the version 0.3.0")
-(>&2 echo "warning: use binary installation instead")
-
-# Create binary:
-PLUGIN_DIR="$(dirname "$0")"
-
-if [ ! -f "$PLUGIN_DIR/git-secret" ]; then
-  cd "$PLUGIN_DIR" && make build && cd ..
-fi
-
-# Add our plugin's bin diretory to user's path
-export PATH="${PATH}:${PLUGIN_DIR}"