Improve incoming webhook slack compatibility (#2972) (#2973)
Improve incoming webhook slack compatibility (#2972) (#2973)

By checking for form urlencoded content instead of JSON, requests without
or with a wrong Content-Type header and a JSON body are correctly parsed.
dotcominternet/platform,dimitertodorov/platform,dotcominternet/platform,rompic/platform,numericube/platform,samogot/platform,asaadmahmoodspin/platform,dimitertodorov/platform,numericube/platform,rompic/platform,asaadmahmoodspin/platform,dimitertodorov/platform,numericube/platform,42wim/platform,dotcominternet/platform,asaadmahmoodspin/platform,daizenberg/platform,samogot/platform,daizenberg/platform,samogot/platform,rompic/platform,dotcominternet/platform,daizenberg/platform,42wim/platform,42wim/platform