Update GitHub Actions checkout to v3 (#352)

* remove obsolete netcoreapp3.1

Author: lahma

.github/workflows/pr.yml

@@ -18,7 +18,7 @@ jobs:
 
     steps:
     - name: Checkout source code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
 
     - name: Generate test cases
       working-directory: ./test/Esprima.Tests.Test262
@@ -35,14 +35,7 @@ jobs:
 
     steps:
     - name: Checkout source code
-      uses: actions/checkout@v2
-
-    - name: Setup .NET
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: |
-          3.1.x
-          6.0.x
+      uses: actions/checkout@v3
 
     - name: Generate test cases
       working-directory: ./test/Esprima.Tests.Test262

.github/workflows/release.yml

@@ -15,14 +15,7 @@ jobs:
 
     steps:
     - name: Checkout source code
-      uses: actions/checkout@v2
-
-    - name: Setup .NET
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: |
-          3.1.x
-          6.0.x
+      uses: actions/checkout@v3
 
     - name: Generate test cases
       working-directory: ./test/Esprima.Tests.Test262

.github/workflows/staging.yml

@@ -18,14 +18,7 @@ jobs:
 
     steps:
     - name: Checkout source code
-      uses: actions/checkout@v2
-
-    - name: Setup .NET
-      uses: actions/setup-dotnet@v1
-      with:
-        dotnet-version: |
-          3.1.x
-          6.0.x
+      uses: actions/checkout@v3
 
     - name: Generate test cases
       working-directory: ./test/Esprima.Tests.Test262

samples/Esprima.Benchmark/Esprima.Benchmark.csproj

@@ -3,7 +3,7 @@
     <AssemblyName>Esprima.Benchmark</AssemblyName>
     <OutputType>Exe</OutputType>
     <IsPackable>false</IsPackable>
-    <TargetFrameworks>net462;netcoreapp3.1;net6.0</TargetFrameworks>
+    <TargetFrameworks>net462;net6.0</TargetFrameworks>
     <LangVersion>latest</LangVersion>
     <AssemblyOriginatorKeyFile>../../src/Esprima.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>