ci: add compiletests for spv1.5 and spv1.6

Author: Firestar99

.github/workflows/ci.yaml

@@ -156,6 +156,10 @@ jobs:
         run: cargo run -p compiletests --release --no-default-features --features "use-installed-tools" -- --target-env spv1.3
       - name: compiletest spv1.4
         run: cargo run -p compiletests --release --no-default-features --features "use-installed-tools" -- --target-env spv1.4
+      - name: compiletest spv1.5
+        run: cargo run -p compiletests --release --no-default-features --features "use-installed-tools" -- --target-env spv1.5
+      - name: compiletest spv1.6
+        run: cargo run -p compiletests --release --no-default-features --features "use-installed-tools" -- --target-env spv1.6
 
   difftest:
     name: Difftest