[gnome-builder] meson-templates: fix cargo.sh usage with Dash

[Christian Hergert <chergert src gnome org>]

commit 4e82af946b99175a80b25555a9e556cdbef46f0f
Author: Christian Hergert <chergert redhat com>
Date:   Thu Jul 2 11:22:09 2020 -0700

    meson-templates: fix cargo.sh usage with Dash
    
    Fixes #1254

 src/plugins/meson-templates/resources/build-aux/cargo.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/plugins/meson-templates/resources/build-aux/cargo.sh 
b/src/plugins/meson-templates/resources/build-aux/cargo.sh
index 2c667a884..b37435f46 100755
--- a/src/plugins/meson-templates/resources/build-aux/cargo.sh
+++ b/src/plugins/meson-templates/resources/build-aux/cargo.sh
@@ -9,7 +9,7 @@ export BUILDTYPE="$4"
 export APP_BIN="$5"
 
 
-if [[ $BUILDTYPE = "release" ]]
+if [ $BUILDTYPE = "release" ]
 then
     echo "RELEASE MODE"
     cargo build --manifest-path \