Fix typos (#554)

CONTRIBUTING.md

@@ -3,7 +3,7 @@ To contribute code changes to this project you will need the following developme
  * [Go](https://golang.org/doc/install)
  * [Docker](https://docs.docker.com/engine/installation/)
  
-As watchtower utilizes go modules for vendor locking, you'll need atleast Go 1.11.
+As watchtower utilizes go modules for vendor locking, you'll need at least Go 1.11.
 You can check your current version of the go language as follows:
 ```bash
   ~ $ go version

docs/private-registries.md

@@ -133,4 +133,4 @@ and for `<PATH_TO_HOME_DIR>/.docker/config.json`:
   }
 ```
 
-*Note:* `osxkeychain` can be changed to your prefered credentials helper.
+*Note:* `osxkeychain` can be changed to your preferred credentials helper.

scripts/lifecycle-tests.sh

@@ -89,7 +89,7 @@ builddocker
 # Run container
 docker run -d -p 0.0.0.0:8888:8888 --name $CONTAINER $IMAGE:latest >> /dev/null
 sleep 1
-echo "Container $CONTAINER is runnning"
+echo "Container $CONTAINER is running"
 
 # Test default value
 RESP=$(curl -s http://localhost:8888)
@@ -126,7 +126,7 @@ docker run -d -p 0.0.0.0:8888:8888 \
 	--label=com.centurylinklabs.watchtower.lifecycle.post-update="echo container > /opt/test/value.txt" \
 	--name $CONTAINER $IMAGE:latest >> /dev/null
 sleep 1
-echo "Container $CONTAINER is runnning"
+echo "Container $CONTAINER is running"
 
 # Test default value
 RESP=$(curl -s http://localhost:8888)
@@ -170,7 +170,7 @@ docker run -d -p 0.0.0.0:8989:8888 \
 	--link $CONTAINER \
 	--name $LINKED_CONTAINER $LINKED_IMAGE:latest >> /dev/null
 sleep 1
-echo "Container $CONTAINER and $LINKED_CONTAINER are runnning"
+echo "Container $CONTAINER and $LINKED_CONTAINER are running"
 
 # Test default value
 RESP=$(curl -s http://localhost:8888)