EmailConfig: Use CanonicalMIMEHeaderKey instead of TitleCasing for headers (#3080)
EmailConfig: Use CanonicalMIMEHeaderKey instead of TitleCasing for headers (#3080)

* EmailConfig: Use CanonicalMIMEHeaderKey instead of TitleCasing for headers

Fixes #3064.

Signed-off-by: Joe Blubaugh <59f4c54a340094bd42f9e195f2641ce2b3c58ec3@grafana.com>

* Remove an unused field.

Signed-off-by: Joe Blubaugh <59f4c54a340094bd42f9e195f2641ce2b3c58ec3@grafana.com>

Signed-off-by: Joe Blubaugh <59f4c54a340094bd42f9e195f2641ce2b3c58ec3@grafana.com>
prometheus/alertmanager,prometheus/alertmanager,prometheus/alertmanager,prometheus/alertmanager