Added action.yml and pack.sh

Signed-off-by: Joe Kutner <jpkutner@gmail.com>

action.yml

@@ -0,0 +1,13 @@
+name: 'Setup Pack CLI'
+description: 'Setup a Pack CLI and add it to the PATH'
+author: 'Buildpacks.io'
+inputs:
+  version:
+    description: 'The Pack version to download and use.'
+    required: true
+    default: '0.14.1'
+runs:
+  using: "composite"
+  steps:
+    - run: ${{ github.action_path }}/dist/pack.sh "${{ inputs.version }}"
+      shell: bash

dist/pack.sh

@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+pack_version="${1}"
+jq_version="1.6"
+crane_version="0.1.4"
+yj_version="5.0.0"
+
+mkdir -p "$HOME/bin"
+
+echo "---> Installing jq ${jq_version}"
+curl \
+  --retry 3 \
+  --output "${HOME}/bin/jq" \
+  --location \
+  --show-error \
+  --silent \
+  "https://github.com/stedolan/jq/releases/download/jq-${jq_version}/jq-linux64"
+chmod +x "${HOME}/bin/jq"
+
+echo "---> Installing crane ${crane_version}"
+curl \
+  --retry 3 \
+  --location \
+  --show-error \
+  --silent \
+  "https://github.com/google/go-containerregistry/releases/download/v${crane_version}/go-containerregistry_Linux_x86_64.tar.gz" \
+  | tar -C "${HOME}/bin/" -xzv crane
+
+echo "---> Installing yj ${yj_version}"
+curl \
+  --retry 3 \
+  --output "${HOME}/bin/yj" \
+  --location \
+  --show-error \
+  --silent \
+  "https://github.com/sclevine/yj/releases/download/v${yj_version}/yj-linux"
+chmod +x "${HOME}/bin/yj"
+
+echo "---> Installing pack ${pack_version}"
+curl \
+  --retry 3 \
+  --location \
+  --show-error \
+  --silent \
+  "https://github.com/buildpacks/pack/releases/download/v${pack_version}/pack-v${pack_version}-linux.tgz" \
+  | tar -C "${HOME}/bin/" -xzv pack
+
+echo "PATH=${HOME}/bin:${PATH}" >> $GITHUB_ENV