chore: bump version to 0.7.7

Skipping 0.7.6 — the CI run for v0.7.6 failed on cargo fmt --check
before any artifact was published, so the tag is retained on GitHub
as a record of the failed release but no crates.io publication exists
for that version.

Author: firstdorsal

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "gtmpl-ng"
-version = "0.7.6"
+version = "0.7.7"
 authors = ["Florian Dieminger <me@fiji-flo.de>", "Paul Colin Hennig <8d_fvfmaa-o2wf_79aqig6g2ki6-09ffkeqmyo3d@vindelicum.eu>"]
 description = "The Golang Templating Language for Rust (fork with line number fix and Helm functions)"
 license = "MIT"