Fix build with vanilla dotnet7

.github/workflows/CI.yml

@@ -3,7 +3,33 @@ name: CI
 on: [push, pull_request, workflow_dispatch]
 
 jobs:
+  build:
+    runs-on: ubuntu-22.04
+    container:
+      image: "ubuntu:22.04"
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Install required dependencies
+      run: |
+        apt update
+        apt install --yes sudo
+        sudo apt install --yes --no-install-recommends git
+        # workaround for https://github.com/actions/runner/issues/2033
+        git config --global --add safe.directory '*'
+    - name: Setup .NET
+      run: |
+        # We need to install `ca-certificates`, otherwise we get these errors in the CI:
+        # Unable to load the service index for source https://api.nuget.org/v3/index.json.
+        # The SSL connection could not be established, see inner exception.
+        # The remote certificate is invalid because of errors in the certificate chain: UntrustedRoot
+        apt install --yes --no-install-recommends ca-certificates
+        apt install --yes --no-install-recommends dotnet7
+    - name: Build
+      run: dotnet build
+
   build_snap:
+    needs: build
     runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v1

src/PackWallet/PackWallet.fsproj

@@ -3,6 +3,7 @@
     <PropertyGroup>
         <OutputType>Exe</OutputType>
         <TargetFramework>net7.0</TargetFramework>
+        <DisableImplicitFSharpCoreReference>true</DisableImplicitFSharpCoreReference>
     </PropertyGroup>
 
     <ItemGroup>