fix(scripts): use a more precise method of grepping

Github recently changed the output of the releases page.

grepping for the exact <a> tag fixes the issue where the wrong tag was being filtered.

Signed-off-by: Matthew Fisher <matt.fisher@microsoft.com>

scripts/get

@@ -80,9 +80,9 @@ checkDesiredVersion() {
   # Use the GitHub releases webpage for the project to find the desired version for this project.
   local release_url="https://github.com/helm/helm/releases/${DESIRED_VERSION:-latest}"
   if type "curl" > /dev/null; then
-    TAG=$(curl -SsL $release_url | awk '/\/tag\//' | grep -v no-underline | head -n 1 | cut -d '"' -f 2 | awk '{n=split($NF,a,"/");print a[n]}' | awk 'a !~ $0{print}; {a=$0}')
+    TAG=$(curl -SsL $release_url | awk '/\/tag\//' | grep -v no-underline | grep "<a href=\"/helm/helm/releases" | head -n 1 | cut -d '"' -f 2 | awk '{n=split($NF,a,"/");print a[n]}' | awk 'a !~ $0{print}; {a=$0}')
   elif type "wget" > /dev/null; then
-    TAG=$(wget -q -O - $release_url | awk '/\/tag\//' | grep -v no-underline | head -n 1 | cut -d '"' -f 2 | awk '{n=split($NF,a,"/");print a[n]}' | awk 'a !~ $0{print}; {a=$0}')
+    TAG=$(wget -q -O - $release_url | awk '/\/tag\//' | grep -v no-underline | grep "<a href=\"/helm/helm/releases" | head -n 1 | cut -d '"' -f 2 | awk '{n=split($NF,a,"/");print a[n]}' | awk 'a !~ $0{print}; {a=$0}')
   fi
   if [ "x$TAG" == "x" ]; then
     echo "Cannot determine ${DESIRED_VERSION} tag."