Use OD 2024.1 by default, run CI on macOS, README updates

.github/workflows/build-and-test.yml

@@ -1,5 +1,5 @@
-# To test changes to the install-opendylan Action we choose an arbitrary
-# project to build and test.
+# To test changes to the install-opendylan Action we choose an arbitrary, relatively
+# simple project to build and test.
 
 name: build-and-test
 
@@ -16,7 +16,11 @@ on:
 
 jobs:
   build-and-test:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [macos-latest, ubuntu-latest]
+
     steps:
 
       - uses: actions/checkout@v4
@@ -29,7 +33,7 @@ jobs:
       # Use the local checkout of install-opendylan as a GitHub Action.
       - uses: ./
 
-      - name: Build test suite app
+      - name: Build test suite
         run: |
           cd hash-algorithms
           dylan update

README.md

@@ -1,3 +1,5 @@
+[![tests](https://github.com/dylan-lang/install-opendylan/actions/workflows/build-and-test.yml/badge.svg)](https://github.com/dylan-lang/install-opendylan/actions/workflows/build-and-test.yml)
+
 # install-opendylan
 
 A GitHub Action to install the Open Dylan compiler (`dylan-compiler`) and
@@ -15,18 +17,14 @@ To install a specific released version:
 ```yaml
     - uses: dylan-lang/install-opendylan@v3
       with:
-        version: 2020.1
         tag: v2020.1.0
 ```
 
-`version` is the version number used in the top-level Open Dylan directory when
-unpacked from the tarball.
-
 `tag` is the exact tag identifying the GitHub release, including the leading
 "v".
 
 **Important:** This Action must be used **after**
-[actions/checkout@v2](https://github.com/actions/checkout) when using the
+[actions/checkout@vN](https://github.com/actions/checkout) when using the
 default `path:` (i.e., the current directory) because `actions/checkout@v2`
 deletes everything in the repo directory first.
 
@@ -44,3 +42,12 @@ included by the `dylan update` command when generating registry files.
 
 See the [hello](https://github.com/cgay/hello) repository for the canonical
 example of how to use this Action.
+
+# Versions
+
+This repository uses standard [Semantic Versioning](https://semver.org), but also
+provides moving tags for each major version for those who want to get the latest Open
+Dylan releases automatically. For example, the "v3" tag always points to the latest
+release with major version 3, e.g., `v3 -> v3.2.1`.  The major version of
+`install-opendylan` only changes when the Action itself is changed incompatibly, as with
+normal SemVer semantics.

action.yml

@@ -4,7 +4,7 @@ inputs:
   tag:
     required: false
     type: string
-    default: v2023.1.0
+    default: v2024.1.0
 
 runs:
   using: composite
@@ -31,7 +31,7 @@ runs:
         echo "dylan-tool: ${PWD}/dylan"
         echo -n "Open Dylan "
         ./dylan-compiler -version
-        echo -n "dylan-tool version: "
+        echo -n "dylan version: "
         ./dylan version
         # https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-system-path
         # Eventually we can add opendylan/bin to the path instead of creating