Added latest tag for docker images

.drone.yml

@@ -7,7 +7,7 @@ clone:
 
 steps:
   - name: archlinux_build
-    image: archlinux_build
+    image: archlinux_build:latest
     pull: if-not-exists
     volumes:
     - name: archlinux_ccache
@@ -22,7 +22,7 @@ steps:
     - make -j2
 
   - name: archlinux_test
-    image: archlinux_build
+    image: archlinux_build:latest
     pull: if-not-exists
     commands:
     # The following command is not required, we included this in the docker 
@@ -55,7 +55,7 @@ volumes:
 
 steps:
   - name: ubuntu_build
-    image: ubuntu
+    image: ubuntu:latest
     pull: if-not-exists
     volumes:
     - name: ubuntu_ccache
@@ -71,7 +71,7 @@ steps:
     - make -j2
 
   - name: ubuntu_test
-    image: ubuntu
+    image: ubuntu:latest
     pull: if-not-exists
     commands:
     # The following commands are not required, we included this in the docker