This PR aims to add `Vary` header in Thumbor response to avoid problems with downstream caches.

Closes https://github.com/thumbor/thumbor/issues/1563
thanks @mpdude 
Should have vary header with auto heif and avif. This PR aims to add `Vary` header in Thumbor response to avoid problems with downstream caches.

Closes https://github.com/thumbor/thumbor/issues/1563
thanks @mpdude 
PNG


IHDRddpTgAMAa cHRMz&u0`:pQ<bKGDtIMEIDATxKLI=
5+<#"bIĸ<&փf<qf<.rF<DcԈaGx(G|63tw5;5]}plѠ"Jer(t LCz~`	W,@
Ȱ@pR
CRS\rDj4`'#'FCw72H1$-Me%@ӛ7'uԐtǸ=9n
ڠ9bHVqwDDh^و
jfH^2ڐHcxۘ-){?YzhHcLBӧ<_ӌj=%2^qZW<'ېK&pUifY\l.Rӣ]gmʕ*2"Pa2+CVVcF߿ۘ!x&JE+&C֬xl߹<%)3:QfJdy_4G!׋:Uan"!7
?ƢE|_>Ɉl$4.ik?8:(31BlH@._que+OP6BnU_8}!>d+Npb'S!۷"^??uW8,[G8LX2-B~Ae+ϜluZ|씭c$`^2%Bv8OVL]Ǐ2ir0bB!>yZ!Gd+(
|5drٷOd/d+0'OjcTVqLQ#[ǩ!]i788 R)'[$]D%f,D23BVV`!((5#/[bӐ|J䛷J,[3B>bddS!}n`4de2oYn`>J<2#GfV׌~J2,[e@'NWXAZkNZYC:-rQ@"0lE#
A#ZL_~]:26x{;2QAݶcu Ħv#쩭&N뜕cL::ğ94hSL4q&pAvVmۦM46Ӏ2NB}8cKXbZl\Ql"k"&zUK,fOU6b$>/eBVEQqC
krg
}Eݺue6'V/hԬp0FUG~HW#ee61y@U؉UlcݭjPEj
jP*ma.-uJ*RZDRC5|XrO'O<]PQTZ&ϞyZta˪E24buĂ-?p|J͝Al/Q##ާZ[
1e~f1##>pׯca\Z<4,\h)b((fi,ZnbHè+X=ΛȊH5GFɆZN.G0n`J.q!|,J{vw8dLJ^ʾ@\iH0BT (+RHO>(z~`XӬQ拹f_%tEXtdate:create2016-07-05T19:17:03+02:00Ʈ#%tEXtdate:modify2016-07-05T19:17:03+02:00IENDB`
PNG


IHDRddpTgAMAa cHRMz&u0`:pQ<bKGDtIMEIDATxKLI=
5+<#"bIĸ<&փf<qf<.rF<DcԈaGx(G|63tw5;5]}plѠ"Jer(t LCz~`	W,@
Ȱ@pR
CRS\rDj4`'#'FCw72H1$-Me%@ӛ7'uԐtǸ=9n
ڠ9bHVqwDDh^و
jfH^2ڐHcxۘ-){?YzhHcLBӧ<_ӌj=%2^qZW<'ېK&pUifY\l.Rӣ]gmʕ*2"Pa2+CVVcF߿ۘ!x&JE+&C֬xl߹<%)3:QfJdy_4G!׋:Uan"!7
?ƢE|_>Ɉl$4.ik?8:(31BlH@._que+OP6BnU_8}!>d+Npb'S!۷"^??uW8,[G8LX2-B~Ae+ϜluZ|씭c$`^2%Bv8OVL]Ǐ2ir0bB!>yZ!Gd+(
|5drٷOd/d+0'OjcTVqLQ#[ǩ!]i788 R)'[$]D%f,D23BVV`!((5#/[bӐ|J䛷J,[3B>bddS!}n`4de2oYn`>J<2#GfV׌~J2,[e@'NWXAZkNZYC:-rQ@"0lE#
A#ZL_~]:26x{;2QAݶcu Ħv#쩭&N뜕cL::ğ94hSL4q&pAvVmۦM46Ӏ2NB}8cKXbZl\Ql"k"&zUK,fOU6b$>/eBVEQqC
krg
}Eݺue6'V/hԬp0FUG~HW#ee61y@U؉UlcݭjPEj
jP*ma.-uJ*RZDRC5|XrO'O<]PQTZ&ϞyZta˪E24buĂ-?p|J͝Al/Q##ާZ[
1e~f1##>pׯca\Z<4,\h)b((fi,ZnbHè+X=ΛȊH5GFɆZN.G0n`J.q!|,J{vw8dLJ^ʾ@\iH0BT (+RHO>(z~`XӬQ拹f_%tEXtdate:create2016-07-05T19:17:03+02:00Ʈ#%tEXtdate:modify2016-07-05T19:17:03+02:00IENDB`