sysutils/ttyd: update to 1.6.1

From ChangeLog: https://github.com/tsl0922/ttyd/releases/tag/1.6.1

• Bump to 1.6.1
• html: add disableLeaveAlert client option
• src/http.c: fix checking pss's len member
• cmake: update git command args
• cmake: fix build without C++
• http: fix build with lws 1.7
• protocol: fix readonly handling
• Fix type declaration
• src: fix lws version check for keep alive
• html: set URL of stylesheet by href
• html: recreate sentry object on zmodem reset
• all: use the static keyword on functions
• protocol: replace uv_try_write with uv_write
• Add -b, --base-path option for reverse proxies
• protocol: fix lws callback compatibility
• server: mute lws 4.0 extensions warning
• html: reuse xterm instance on reconnect
• Add 64-bit ARM

Reported by: portscout