Fix when input directories are not found (#20)

* Fix when input directories are not found

* Update main.jl

Co-authored-by: Ian Butterworth <i.r.butterworth@gmail.com>

Co-authored-by: Ian Butterworth <i.r.butterworth@gmail.com>

main.jl

@@ -9,8 +9,12 @@ using CoverageTools
 directories = get(ENV, "INPUT_DIRECTORIES", "src,ext")
 dirs = filter!(!isempty, split(directories, ","))
 for dir in dirs
-    isdir(dir) || error("directory \"$dir\" not found!")
+    if dir == "ext"
+        continue  # Silently skip this directory
+    elseif !isdir(dir)
+        error("directory \"$dir\" not found!")
+    end
 end
-
+filter!(isdir, dirs)
 pfs = mapreduce(process_folder, vcat, dirs)
 LCOV.writefile("lcov.info", pfs)