fix: minor fix of release.sh

Previously version of FC obtained from binary in `release.sh`
contained `v` (so it was `v.1.4.0`). But in `Cargo.toml`
of FC version was `1.4.0`. Because of this difference release
process was failing. This change fixes this issue.

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

tools/release.sh

@@ -52,7 +52,7 @@ function strip-and-split-debuginfo {
 }
 
 function get-firecracker-version {
-    (cd src/firecracker; cargo pkgid | cut -d# -f2 | cut -d: -f2)
+    (cd src/firecracker; cargo pkgid | cut -d# -f2 | (echo -n v; cut -d: -f2))
 }
 
 #### MAIN ####