devel/got: update to 0.48

User-visible changes:

• tog log: terminate author field at '>' in case there is no '@'
• make 'got clone' pin the fetched branch in got.conf(5)
• allow the 'got fetch' -l option together with the -q option
• store branches passed via 'got clone -b' in got.conf(5) and git-config(1)
• work around spurious ACK responses from git servers in got-fetch-pack
• add a 'fetch-all-branches' configuration setting to got.conf(5)
• add a 'reference' directive to remote repositories in got.conf(5)
• fix 'got up -c commit path' deleting unrelated files
• fix 'tog blame' segfault upon empty input file
• let 'got clone' write gitconfig directives that match the generated got.conf