ci: Add oasis-install

Author: amela

.github/workflows/install-oasis.yml

@@ -0,0 +1,30 @@
+name: install-oasis
+on:
+  workflow_call:
+    inputs:
+      release_tag:
+        required: false
+        type: string
+  # A push occurs to one of the matched branches.
+  push:
+    branches:
+      - master
+      - stable/*
+  # Or when a pull request event occurs for a pull request against one of the
+  # matched branches.
+  pull_request:
+    branches:
+      - master
+      - stable/*
+jobs:
+  install:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Oasis CLI (latest or pinned)
+        run: |
+          TAG="${{ inputs.release_tag }}"
+          echo "Input length: ${#TAG}"
+          API="https://api.github.com/repos/oasisprotocol/cli/releases/${TAG:+tags/}${TAG:-latest}"
+          # ...same download logic...
+      - name: Expose PATH
+        run: echo "$PWD" >> "$GITHUB_PATH"