Strip Go symbol table from release binaries

Adds -s to the goreleaser ldflags alongside the existing -w. Per
maintainer testing on #2109, building with -s -w shrinks the tkn
binary from ~207MB to ~147MB (~30%) compared to the current -w-only
default.

Signed-off-by: alliasgher <alliasgher123@gmail.com>

Author: alliasgher

.goreleaser.yml

@@ -16,7 +16,7 @@ builds:
   - s390x
   - ppc64le
   ldflags:
-  - -w -X github.com/tektoncd/cli/pkg/cmd/version.clientVersion={{.Version}}
+  - -s -w -X github.com/tektoncd/cli/pkg/cmd/version.clientVersion={{.Version}}
 archives:
 - name_template: >-
     {{- .Binary }}_