Dont error out on version check

[mandopaloooza]

GitHub outage caused a fatal crash during sdpctl version check, preventing the actual command to terminate early.

09:31:33 panic: runtime error: index out of range [0] with length 0
09:31:33 09:31:33 goroutine 1 [running]:
09:31:33 github.com/appgate/sdpctl/pkg/configuration.(*Config).CheckForUpdate(0xc0000fa480, {0x599e73713a98, 0xc0000ae020}, 0xc0000b6ed0, {0x599e732d05b0, 0xe})
09:31:33 github.com/appgate/sdpctl/pkg/configuration/configuration.go:468 +0x888
09:31:33 github.com/appgate/sdpctl/cmd.NewCmdRoot.rootPersistentPreRunEFunc.func3(0xc00025e608, {0xc000219030, 0x0, 0x7})
09:31:33 github.com/appgate/sdpctl/cmd/root.go:397 +0x6a5
09:31:33 github.com/spf13/cobra.(*Command).execute(0xc00025e608, {0xc000218fc0, 0x7, 0x7})
09:31:33 github.com/spf13/cobra@v1.10.2/command.go:986 +0x98f
09:31:33 github.com/spf13/cobra.(*Command).ExecuteC(0xc000220008)
09:31:33 github.com/spf13/cobra@v1.10.2/command.go:1148 +0x465
09:31:33 github.com/appgate/sdpctl/pkg/cmdutil.ExecuteCommand(0xc0000b9970?)
09:31:33 github.com/appgate/sdpctl/pkg/cmdutil/execute.go:44 +0x1f
09:31:33 github.com/appgate/sdpctl/cmd.Execute()
09:31:33 github.com/appgate/sdpctl/cmd/root.go:269 +0x1a7
09:31:33 main.main()
09:31:33 ./main.go:10 +0x13