docs: add a note about Semgrep's strange behavior (#15)

Describes the purpose of the `experimental` flag and its correlation
to output files.

Author: droguljic

src/scripts/analyze-code.sh

@@ -2,6 +2,12 @@
 
 ########### DEFAULTS ###########
 
+# The `experimental` flag is needed for Semgrep to work, otherwise
+# for unknown reason it will fail with exit code 2. This behavior
+# is only observed in CI environment.
+# When the `experimental` flag is set, saving the output to the
+# file will not work and is just silently ignored.
+
 ARGS="--experimental --error --strict --metrics off"
 
 ########### VERBOSE ###########