fix: grass78 -> grass79

docker/alpine/Dockerfile_alpine

@@ -176,10 +176,10 @@ RUN echo "  => Configure and compile grass";\
     rm -rf /var/cache/apk/*; \
     rm -rf /root/.cache; \
     # Remove unnecessary grass files
-    rm -rf /usr/local/grass78/demolocation; \
-    rm -rf /usr/local/grass78/fonts; \
-    rm -rf /usr/local/grass78/gui; \
-    rm -rf /usr/local/grass78/share;
+    rm -rf /usr/local/grass79/demolocation; \
+    rm -rf /usr/local/grass79/fonts; \
+    rm -rf /usr/local/grass79/gui; \
+    rm -rf /usr/local/grass79/share;
 
 
 # Unset environmental variables to avoid later compilation issues