put-object should set correct content-type

[simonw]

I got this working, but the files I upload with s3-credentials put-object all have Content-Type: binary/octet-stream.

Originally posted by @simonw in #42 (comment)

[simonw]

I can guess the type from the file extension using mimetypes: https://docs.python.org/3/library/mimetypes.html#mimetypes.guess_type

[simonw]

But for reading from stdin I will let the user set --content-type something instead.

[simonw]

Prototype worked:

echo "<h1>Hello world" | \
  s3-credentials put-object simonwillison-public-bucket \
    -a public-bucket-creds.json hello.html - \
    --content-type text/html

http://s3.amazonaws.com/simonwillison-public-bucket/hello.html

This is for a bucket created using the new experimental --public-bucket option from:

• Support making the bucket public, in that anyone can download files unauthenticated if they know the URL #42

[simonw]

I wrote an integration test for #42 which also covers this.

[simonw]

Added tests in 6e0a2c2