Add support for linux, test on ubuntu

Author: robhogan

.github/workflows/test.yml

@@ -103,4 +103,19 @@ jobs:
         podfile-path: __tests__/podfile-example/Podfile3.lock
 
     - name: Validate version
-      run: pod --version | grep "1.9.1"
+      run: pod --version | grep "1.9.1"
+
+  ubuntu-install:
+    name: install latest version
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+
+    - name: setup-cocoapods
+      uses: ./
+      with:
+        version: latest
+
+    - name: Validate version
+      run: pod --version

dist/index.js

@@ -1573,8 +1573,8 @@ const core = __importStar(__webpack_require__(470));
 const installer_1 = __webpack_require__(749);
 const run = async () => {
     try {
-        if (process.platform !== "darwin") {
-            throw new Error(`This task is intended only for macOS platform. It can't be run on '${process.platform}' platform`);
+        if (process.platform !== "darwin" && process.platform !== "linux") {
+            throw new Error(`This task is intended for macOS and linux platforms. It can't be run on '${process.platform}' platform`);
         }
         let versionSpec = core.getInput("version", { required: false });
         const podfilePath = core.getInput("podfile-path", { required: false });

src/setup-cocoapods.ts

@@ -3,8 +3,8 @@ import { CocoapodsInstaller } from "./installer";
 
 const run = async (): Promise<void> => {
     try {
-        if (process.platform !== "darwin") {
-            throw new Error(`This task is intended only for macOS platform. It can't be run on '${process.platform}' platform`);
+        if (process.platform !== "darwin" && process.platform !== "linux") {
+            throw new Error(`This task is intended for macOS and linux platforms. It can't be run on '${process.platform}' platform`);
         }
 
         let versionSpec = core.getInput("version", { required: false });