ci: install grub2-tools-minimal to test test_write_grubenv()

Author: HuijingHei

.cci.jenkinsfile

@@ -17,6 +17,7 @@ parallel build: {
       }
       stage("Unit tests") {
         shwrap("""
+          dnf install -y grub2-tools-minimal
           cargo test
         """)
       }

.github/workflows/rust.yml

@@ -32,6 +32,10 @@ jobs:
         uses: dtolnay/rust-toolchain@v1
         with:
           toolchain: stable
+      - name: Install grub2
+        run: |
+          set -xeu
+          dnf install -y grub2-tools-minimal
       - name: Cache build artifacts
         uses: Swatinem/rust-cache@v2
       - name: cargo build
@@ -49,6 +53,10 @@ jobs:
         uses: dtolnay/rust-toolchain@v1
         with:
           toolchain: stable
+      - name: Install grub2
+        run: |
+          set -xeu
+          dnf install -y grub2-tools-minimal
       - name: Cache build artifacts
         uses: Swatinem/rust-cache@v2
       - name: cargo build (release)
@@ -74,6 +82,10 @@ jobs:
           toolchain: ${{ env.MSRV }}
       - name: Cache build artifacts
         uses: Swatinem/rust-cache@v2
+      - name: Install grub2
+        run: |
+          set -xeu
+          dnf install -y grub2-tools-minimal
       - name: cargo build (release)
         run: cargo build --all-targets --release
       - name: cargo test (release)
@@ -111,6 +123,10 @@ jobs:
         uses: dtolnay/rust-toolchain@v1
         with:
           toolchain: ${{ matrix.channel }}
+      - name: Install grub2
+        run: |
+          set -xeu
+          dnf install -y grub2-tools-minimal
       - name: Cache build artifacts
         uses: Swatinem/rust-cache@v2
       - name: cargo build