[DO-971] ffmpeg recipe with requirements (!9)

Co-authored-by: aleksandr.vodyanov <aleksandr.vodyanov@avroid.tech>
Reviewed-on: https://git.avroid.tech/Conan/conan_build/pulls/9

recipes/dav1d/all/test_package/test_package.c

@@ -0,0 +1,9 @@
+#include "dav1d/dav1d.h"
+
+#include <stdio.h>
+
+int main()
+{
+    printf("dav1d version: %s\n", dav1d_version());
+    return 0;
+}