Update 'build_upload_mithril_artifact' action

Avoid unwanted usage of features when building the artifacts from the workspace.
Split in 2 phases: tooling first and then distribution.

.github/workflows/actions/build-upload-mithril-artifact/action.yml

@@ -4,7 +4,7 @@ inputs:
   build-args:
     description: Arguments to pass to 'cargo build'
     required: false
-    default: ''
+    default: '-p mithril-aggregator -p mithril-client -p mithril-common -p mithril-signer -p mithril-stm'
 runs:
   using: "composite"
   steps:
@@ -14,10 +14,10 @@ runs:
         pip3 install toml
         python3 ./.github/workflows/scripts/edit-cargo-toml-version.py -l $(echo ${{ github.sha }} | cut -c1-7)
 
-    - name: Cargo build
+    - name: Cargo build - Distribution
       shell: bash
       run: cargo build --release ${{ inputs.build-args }}
-
+        
     - name: Publish Mithril Distribution (${{ runner.os }}-${{ runner.arch }})
       uses: actions/upload-artifact@v3
       with:

.github/workflows/ci.yml

@@ -31,6 +31,11 @@ jobs:
           cache-version: ${{ secrets.CACHE_VERSION }}
           cargo-tools: cargo-deb
 
+      # We separate the build in 2 steps as we want to avoid side effects with Rust feature unification.
+      - name: Cargo build - Tooling
+        shell: bash
+        run: cargo build --release --workspace --exclude mithril-aggregator --exclude mithril-client --exclude mithril-signer --exclude mithril-stm
+
       - name: Build Mithril workspace & publish artifacts
         uses: ./.github/workflows/actions/build-upload-mithril-artifact