Add action, dockerfile, entrypoint

Dockerfile

@@ -0,0 +1,8 @@
+FROM python:3-alpine
+
+RUN pip install yamllint && \
+    rm -rf ~/.cache/pip
+
+ADD entrypoint.sh /entrypoint.sh
+
+ENTRYPOINT ["/entrypoint.sh"]

action.yml

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+name: 'YAMLLint'
+description: 'Validate YAML syntax'
+author: 'ibiqlik'
+
+inputs:
+  file_or_dir:
+    description: 'File(s) or Directory'
+    required: true
+  config_file:
+    description: 'Path to custom configuration'
+    required: false
+  config_data:
+    description: 'Custom configuration (as YAML source)'
+    required: false
+  format:
+    description: 'Format for parsing output [parsable,standard]'
+    required: false
+  strict:
+    description: 'Return non-zero exit code on warnings as well as errors'
+    required: false
+
+runs:
+  using: 'docker'
+  image: 'Dockerfile'

entrypoint.sh

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+#!/bin/sh -l
+
+if [ ! -z $INPUT_STRICT ]; then
+    STRICT="-s"
+fi
+
+yamllint $INPUT_CONFIG_FILE $INPUT_CONFIG_DATA $INPUT_FORMAT $STRICT $INPUT_FILE_OR_DIR