updated GHA

Author: topepo

.github/workflows/R-CMD-check.yaml

@@ -1,7 +1,10 @@
 on:
   push:
+    branches:
+      - master
   pull_request:
-    types: [opened, synchronize, reopened]
+    branches:
+      - master
 
 name: R-CMD-check
 
@@ -18,7 +21,7 @@ jobs:
           - {os: macOS-latest,   r: 'release'}
           - {os: windows-latest, r: 'release'}
           - {os: windows-latest, r: '3.6'}
-          - {os: ubuntu-16.04,   r: 'devel', rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
+          - {os: ubuntu-16.04,   r: 'devel', rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest", http-user-agent: "R/4.0.0 (ubuntu-16.04) R (4.0.0 x86_64-pc-linux-gnu x86_64 linux-gnu) on GitHub Actions" }
           - {os: ubuntu-16.04,   r: 'release', rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
           - {os: ubuntu-16.04,   r: 'oldrel',  rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
           - {os: ubuntu-16.04,   r: '3.5',     rspm: "https://packagemanager.rstudio.com/cran/__linux__/xenial/latest"}
@@ -34,6 +37,7 @@ jobs:
       - uses: r-lib/actions/setup-r@master
         with:
           r-version: ${{ matrix.config.r }}
+          http-user-agent: ${{ matrix.config.http-user-agent }}
 
       - uses: r-lib/actions/setup-pandoc@master
 
@@ -79,7 +83,7 @@ jobs:
         run: |
           reticulate::conda_create('r-reticulate', packages = c('python==3.6.9'))
           tensorflow::install_tensorflow(version='1.14.0')
-        shell: Rscript {0}
+        shell: Rscript {0}        
 
       - name: Session info
         run: |