Use ponyup to install pony tools in macOS environments

As of ponyc 0.34.0 we are no longer maintaining the homebrew ponyc
formula so it will get out of date. By using ponyup, we can stay
up-to-date with the latest releases.

Closes #102

.ci-scripts/macOS-install-pony-tools.bash

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+curl --proto '=https' --tlsv1.2 -sSf https://raw.githubusercontent.com/ponylang/ponyup/latest-release/ponyup-init.sh | sh
+
+export PATH="$HOME/.local/share/ponyup/bin/:$PATH"
+
+ponyup update ponyc release
+ponyup update pony-stable release

.ci-scripts/release/x86-64-apple-darwin-nightly.bash

@@ -9,11 +9,17 @@
 #
 # - bash
 # - cloudsmith-cli
+# - GNU coreutils
 # - GNU gzip
 # - GNU make
+# - libressl
 # - ponyc
+# - pony-stable
 # - GNU tar
 
+# add ponyup to PATH to get ponyc and pony-stable
+export PATH="$HOME/.local/share/ponyup/bin/:$PATH"
+
 set -o errexit
 
 # Pull in shared configuration specific to this repo

.ci-scripts/release/x86-64-apple-darwin-release.bash

@@ -9,11 +9,17 @@
 #
 # - bash
 # - cloudsmith-cli
+# - GNU coreutils
 # - GNU gzip
 # - GNU make
+# - libressl
 # - ponyc
+# - pony stable
 # - GNU tar
 
+# add ponyup to PATH to get ponyc and pony-stable
+export PATH="$HOME/.local/share/ponyup/bin/:$PATH"
+
 set -o errexit
 
 # Pull in shared configuration specific to this repo

.github/workflows/nightlies.yml

@@ -22,8 +22,8 @@ jobs:
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v1
-      - name: brew install pony tools
-        run: brew install ponyc pony-stable
+      - name: install pony tools
+        run:  bash .ci-scripts/macOS-install-pony-tools.bash
       - name: brew install dependencies
         run: brew install coreutils libressl python
       - name: pip install dependencies

.github/workflows/release.yml

@@ -23,8 +23,8 @@ jobs:
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v1
-      - name: brew install pony tools
-        run: brew install ponyc pony-stable
+      - name: install pony tools
+        run:  bash .ci-scripts/macOS-install-pony-tools.bash
       - name: brew install dependencies
         run: brew install coreutils libressl python
       - name: pip install dependencies