use latest fly-go and include new "es256" key type for "fly secrets keys" commands.

[timflyio]

Change Summary

What and Why: Include support for the new "es256" key type that the machines "secretkeys" API now supports.

How: Use the latest fly-go library, and include the "es256" key type in flyctl's key type table.

Related to:

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Documentation

• Fresh Produce
• In superfly/docs, or asked for help from docs team
• n/a

[timflyio]

Example listing with the new key type:

$ flydbg secrets keys list -a testkms
build
run: /home/newsham/workspace/superfly/flyctl/flydbg: flydbg secrets keys list -a testkms
LABEL         	NAME        	VERSION	TYPE                        
es256v1       	es256       	1      	signing (es256)            	
myencrkeyv1   	myencrkey   	1      	encrypting (nacl_secretbox)	
mysigningkeyv0	mysigningkey	0      	signing (nacl_auth)        	
mysigningkeyv1	mysigningkey	1      	signing (nacl_auth)