fix: stop snapshot builds claiming to be a release

.Tag is the last release tag even under --snapshot, so every snapshot stamped
v1.1.0 and IsRelease then pinned doc URLs to a tag the build has nothing to do
with. Snapshots now stamp the snapshot version, v1.1.0-SNAPSHOT-090323e.

Stamping the literal `dev` would not have worked: resolve() treats dev as
unstamped and replaces it from debug.ReadBuildInfo, which yields a Go
pseudo-version — correct, but it would show up in --version and the User-Agent
as v1.1.1-0.20260730115333-090323eb8be5+dirty.

beep boop

Author: khvn26

.goreleaser.yaml

@@ -6,10 +6,9 @@ builds:
       - CGO_ENABLED=0
     flags:
       - -trimpath
-    # .Tag, not .Version: `flagsmith --version` should print the tag verbatim,
-    # and internal/version.IsRelease expects the leading v.
     ldflags:
-      - -s -w -X github.com/Flagsmith/flagsmith-cli/internal/version.Version={{ .Tag }}
+      - >-
+        -s -w -X github.com/Flagsmith/flagsmith-cli/internal/version.Version={{ if .IsSnapshot }}v{{ .Version }}{{ else }}{{ .Tag }}{{ end }}
     mod_timestamp: "{{ .CommitTimestamp }}"
     goos:
       - linux