fix typo in cam challenge excercise 6

Author: cecilehannay

notebooks/challenge/cam/exercise_6.ipynb

@@ -150,7 +150,7 @@
     "\n",
     "if (cape(i) > capelmt_mask) then \n",
     "    lengath = lengath + 1 \n",
-    "    deep(lengath) = i \n",
+    "    ideep(lengath) = i \n",
     "end if\n",
     "\n",
     "write(iulog,*) 'HELLO WORLD'\n",