CI/CD: Use specific image in .drone.yml.

Signed-off-by: Grzegorz Kowal <grzegorz@amuncode.org>

.drone.yml

@@ -16,7 +16,7 @@ trigger:
 
 steps:
   - name: build with make
-    image: ubuntu-hpc
+    image: ubuntu-hpc:1
     commands:
       - cd ./build
       - cp -al make.default make.config
@@ -31,7 +31,7 @@ steps:
       - make MPI=Y NDIMS=3 -j 4
 
   - name: build with cmake
-    image: ubuntu-hpc
+    image: ubuntu-hpc:1
     commands:
       - mkdir ./build-cmake/
       - cd ./build-cmake/