fix(mps-model-server-plugin): extend supported range to MPS 2020.3

The plugin declared to be compatible with MPS versions 2021.1 - 2022.3.
Extended that range to include MPS 2020.3 and also extended the workflow
to test the compatibility.

Author: slisson

.github/workflows/mps-compatibility.yaml

@@ -0,0 +1,34 @@
+name: MPS compatibility
+
+on:
+  push:
+    branches:
+      - 'main'
+  pull_request: {}
+  # allow manual execution just in case
+  workflow_dispatch:
+
+jobs:
+  build-mps-components:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up JDK 11
+        uses: actions/setup-java@v3
+        with:
+          distribution: 'temurin'
+          java-version: '11'
+      - name: Build with MPS 2020.3.6
+        run: ./gradlew :mps-model-adapters:build :mps-model-server-plugin:build -Pmps.version=2020.3.6
+      - name: Build with MPS 2021.1.4
+        run: ./gradlew :mps-model-adapters:build :mps-model-server-plugin:build -Pmps.version=2021.1.4
+      - name: Build with MPS 2021.2.6
+        run: ./gradlew :mps-model-adapters:build :mps-model-server-plugin:build -Pmps.version=2021.2.6
+      - name: Build with MPS 2021.3.3
+        run: ./gradlew :mps-model-adapters:build :mps-model-server-plugin:build -Pmps.version=2021.3.3
+      - name: Build with MPS 2022.2
+        run: ./gradlew :mps-model-adapters:build :mps-model-server-plugin:build -Pmps.version=2022.2
+      - name: Build with MPS 2022.3
+        run: ./gradlew :mps-model-adapters:build :mps-model-server-plugin:build -Pmps.version=2022.3

.github/workflows/mps-model-adapters.yaml

@@ -3,7 +3,22 @@ plugins {
     id("org.jetbrains.intellij") version "1.15.0"
 }
 
-val mpsVersion = "2021.1.4"
+val mpsToIdeaMap = mapOf(
+    "2020.3.6" to "203.8084.24", // https://github.com/JetBrains/MPS/blob/2020.3.6/build/version.properties
+    "2021.1.4" to "211.7628.21", // https://github.com/JetBrains/MPS/blob/2021.1.4/build/version.properties
+    "2021.2.6" to "212.5284.40", // https://github.com/JetBrains/MPS/blob/2021.2.5/build/version.properties (?)
+    "2021.3.3" to "213.7172.25", // https://github.com/JetBrains/MPS/blob/2021.3.3/build/version.properties
+    "2022.2" to "222.4554.10", // https://github.com/JetBrains/MPS/blob/2021.2.1/build/version.properties
+    "2022.3" to "223.8836.41", // https://github.com/JetBrains/MPS/blob/2022.3.0/build/version.properties (?)
+)
+// use the given MPS version, or 2022.2 (last version with JAVA 11) as default
+val mpsVersion = project.findProperty("mps.version")?.toString().takeIf { !it.isNullOrBlank() } ?: "2020.3.6"
+if (!mpsToIdeaMap.containsKey(mpsVersion)) {
+    throw GradleException("Build for the given MPS version '$mpsVersion' is not supported.")
+}
+// identify the corresponding intelliJ platform version used by the MPS version
+val ideaVersion = mpsToIdeaMap.getValue(mpsVersion)
+println("Building for MPS version $mpsVersion and IntelliJ version $ideaVersion")
 
 dependencies {
     implementation(project(":model-server-lib"))
@@ -19,7 +34,7 @@ dependencies {
 intellij {
 
     // IDEA platform version used in MPS 2021.1.4: https://github.com/JetBrains/MPS/blob/2021.1.4/build/version.properties#L11
-    version.set("211.7628.21")
+    version.set(ideaVersion)
 
     // type.set("IC") // Target IDE Platform
 
@@ -32,7 +47,7 @@ tasks {
     }
 
     patchPluginXml {
-        sinceBuild.set("211")
+        sinceBuild.set("203")
         untilBuild.set("231.*")
     }