R echo client tests (#17629)

* add r echo api client sample

* add r workflow

* fix

* add env

* set r version

* install curl

* install dep

* fix

* comment out installation

samples/client/echo_api/r/.github/workflows/r-client.yaml

@@ -0,0 +1,33 @@
+# This file is automatically generated by openapi-generator (https://openapi-generator.tech)
+#
+# Based on https://github.com/r-lib/actions/tree/v2/examples
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+name: R-CMD-check
+
+jobs:
+  R-CMD-check:
+    runs-on: ubuntu-latest
+    env:
+      R_KEEP_PKG_SOURCE: yes
+    steps:
+      - uses: actions/checkout@v2
+      - uses: r-lib/actions/setup-r@v2
+        with:
+          use-public-rspm: true
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: any::rcmdcheck, any::roxygen2, any::lintr, local::.
+          needs: check, roxygen2, lint
+      - name: Lint
+        run: lintr::lint_package()
+        shell: Rscript {0}
+      - name: Roxygenize
+        run: |
+          roxygen2::roxygenize('.', roclets = c('rd', 'collate', 'namespace'))
+        shell: Rscript {0}
+      - uses: r-lib/actions/check-r-package@v2