Remove redundant globs from github release artifact list (#55)

The "Create Release" github action contained redundant file globs which listed the same release artifact multiple times.  For [some reason](softprops/action-gh-release#210), this causes the action to encounter a 404 error and fail.

Remove the redundant globs so that each file is listed only once.

Signed-off-by: Alex Leong <alex@buoyant.io>

Author: adleong

.github/workflows/release.yml

@@ -153,9 +153,7 @@ jobs:
           ./target/release/linkerd-smi-*.tgz
           ./target/release/linkerd-smi-*.tgz.sha256
           ./target/release/linkerd-smi-*-darwin*
-          ./target/release/linkerd-smi-*-darwin*.sha256
           ./target/release/linkerd-smi-*-linux-*
-          ./target/release/linkerd-smi-*-linux-*.sha256
           ./target/release/linkerd-smi-*-windows.exe
           ./target/release/linkerd-smi-*-windows.exe.sha256
   chart_deploy: