Add support for .avif file format

[gabriel-vasile]

1. Specify the MIME type and extension for which to add support
   image/avif .avif
2. Share an example file
   ...
3. Optionally, add a reference to the specification of the file format.
   https://www.iana.org/assignments/media-types/image/avif
   https://en.wikipedia.org/wiki/AV1#AV1_Image_File_Format_(AVIF)

[vansante]

I took a stab at this: #160

[mhf-ir]

it's wrong result:

package main

import (
	"fmt"

	"github.com/gabriel-vasile/mimetype"
)

func main() {

	files := []string{
		"testdata/avif.avif", // application/octet-stream
		"testdata/avifsequence.avif", // application/octet-stream
	}

	for _, p := range files {
		mtype, _ := mimetype.DetectFile(p)
		fmt.Println(mtype.String())
	}

}

sweb@sweb-laptop:/sweb/projects/sample$ cat go.sum 
github.com/gabriel-vasile/mimetype v1.4.0 h1:Cn9dkdYsMIu56tGho+fqzh7XmvY2YyGU0FnbhiOsEro=
github.com/gabriel-vasile/mimetype v1.4.0/go.mod h1:fA8fi6KUiG7MgQQ+mEWotXoEOvmxRtOJlERCzSmRvr8=
golang.org/x/net v0.0.0-20210505024714-0287a6fb4125/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
golang.org/x/net v0.0.0-20220105145211-5b0dc2dfae98 h1:+6WJMRLHlD7X7frgp7TUZ36RnQzSf9wVVTNakEp+nqY=
golang.org/x/net v0.0.0-20220105145211-5b0dc2dfae98/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
sweb@sweb-laptop:/sweb/projects/sample$ cat go.mod 
module github.com/org/sample

go 1.17

require (
        github.com/gabriel-vasile/mimetype v1.4.0 // indirect
        golang.org/x/net v0.0.0-20220105145211-5b0dc2dfae98 // indirect
)
sweb@sweb-laptop:/sweb/projects/sample$ 

Env:

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 21.10
Release:	21.10
Codename:	impish
$ go version
go version go1.17.1 linux/amd64

[gabriel-vasile]

Hi @mhf-ir
.avif support was added in #210, but it is not yet released.
You can wait for the new release or update manually to the latest commit:

go get github.com/gabriel-vasile/mimetype@db2464c28aec

I'm going to close this issue but feel free to open a new one if it's still not detecting.