DEP5: Add OFL as an example

Instead of OFL, there is a case that SIL-1.1 or SIL-OPEN-FONT are specified for font packages.

• https://codesearch.debian.net/search?q=SIL-1.1+path%3Adebian%2Fcopyright&literal=1&perpkg=1
• https://codesearch.debian.net/search?q=OPEN-FONT+path%3Adebian%2Fcopyright&literal=1

Not to make mis-understanding, add OFL to the table.

Signed-off-by: Kentaro Hayashi kenhys@xdump.org