[chore]fix semconv script (open-telemetry#10241)

The automation script that runs on a cron to auto-generate PRs for new
semconv updates has been failing since it was created. This PR fixes a
couple of issues w/ the workflow that were preventing it from working.

---------

Signed-off-by: Alex Boten <223565+codeboten@users.noreply.github.com>

.github/workflows/generate-semantic-conventions-pr.yaml

@@ -21,15 +21,14 @@ jobs:
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
-          # version in this repo are prefixed with v
           latest_version=v$(gh release view \
                                --repo open-telemetry/semantic-conventions \
                                --json tagName \
                                --jq .tagName \
                              | sed 's/^v//')
 
-          rc=$(find semconv -name $latest_version | grep .)
-          if $rc == 0; then
+          found=$(find semconv -name $latest_version)
+          if [[ $found =~ $latest_version ]]; then
             already_added=true
           fi
 
@@ -60,8 +59,9 @@ jobs:
       - name: Checkout semantic-convention
         uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4.1.6
         with:
-          repository: open-telemetry/semantic-convention
+          repository: open-telemetry/semantic-conventions
           path: tmp-semantic-conventions
+          fetch-depth: 0
 
       - name: Update version
         env: